[DESCRIPTION] Exhibit 4


Prepared by and Return to:
Gregory W. Glass
Sobering, White & Luczak, P.A.
201 South Orange Ave., Ste. 1000
Orlando, FL 32801

- --------------------------------------------------------------------------------

                       FLORIDA WATER SERVICES CORPORATION,
                formerly known as Southern States Utilities, Inc.

                                       to

                         SUNTRUST BANK, CENTRAL FLORIDA,
                              NATIONAL ASSOCIATION,



                  Successor to NationsBank of Georgia, National
                Association, as Trustee under Indenture dated as
                                of March 1, 1993.


                         -------------------------------

                          SECOND SUPPLEMENTAL INDENTURE



                 Relating to up to $10,000,000 Principal Amount
                     of First Mortgage Bonds, 8.137% Series
                                due July 31, 2022


                         -------------------------------

                           Dated as of March 31, 1997

- --------------------------------------------------------------------------------



                         SECOND SUPPLEMENTAL INDENTURE

         THIS  SECOND   SUPPLEMENTAL   INDENTURE   (the  "Second   Supplemental
Indenture")  is made and entered  into as of the 31st day of March,  1997 by and
between (i) FLORIDA WATER SERVICES CORPORATION, a Florida corporation, formerly
known as Southern States Utilities,  Inc. (hereinafter called the "Company") and
(ii)  SUNTRUST  BANK,  CENTRAL  FLORIDA,  NATIONAL  ASSOCIATION,  successor  to
NationsBank of Georgia, National Association, as Trustee (the "Trustee").

        WHEREAS,  the Company has executed and delivered that certain  Indenture
dated as of March 1, 1993 (the "Original  Indenture") to Nationsbank of Georgia,
National Association, a national banking association (the "Original Trustee") to
secure the payment of Securities  issued or to be issued under and in accordance
with the provisions  thereof,  which Indenture was recorded in multiple  Florida
Counties,  all as set forth on  Composite  Exhibit A attached  hereto and made a
part hereof,

         WHEREAS,  pursuant  to the  terms  of  Section  1701  of  the  Original
Indenture,  the Company and the Original Trustee entered into that certain First
Supplemental Indenture (the "First Supplemental Indenture") dated as of March 1,
1993,  recorded as set forth on Composite  Exhibit A,  relating to those certain
First Mortgage Bonds Variable Rate Series Due December 31, 1993 (the "Securities
of the First  Series") and those certain First  Mortgage Bonds 8.73% Series due
January  31,  2013  (the  "Securities  of  the  Second  Series").  The  Original
Indenture,  as supplemented by the First Supplemental  Indenture, is hereinafter
referred to as the  "Supplemented  Indenture";  the Supplemented  Indenture,  as
further  supplemented  by this Second  Supplemental  Indenture,  is  hereinafter
referred to as the "Indenture";

        WHEREAS,  the Securities of the First Series have been fully retired and
the  Securities  of the  Second  Series  in the  aggregate  principal  amount of
Forty-Five Million Dollars  ($45,000,000.00)  are owned and held by CoBank, ACB,
formerly known as National Bank for Cooperatives ("CoBank");

         WHEREAS, pursuant to that certain Agreement of Resignation, Appointment
and Acceptance dated December 4, 1995,  among the Company,  the Original Trustee
and The Bank of New York (the "Intermediate  Trustee"), the Intermediate Trustee
succeeded to all of the rights,  duties and obligations of the Original  Trustee
under the Indenture;

         WHEREAS, pursuant to that certain Agreement of Resignation, Appointment
and Acceptance dated March 31, 1996, among the Company, the Intermediate Trustee
and  the  Trustee,  the  Trustee  succeeded  to all of the  rights,  duties  and
obligations of the Intermediate Trustee under the Indenture;

         WHEREAS,  Section  1701 of the  Original  Indenture  provides  that the
Company and the Trustee, at any time and from time to time, may enter into one 
or more indentures  supplemental to the Original Indenture, for various purposes
including  to correct or amplify  the  description  of any  property at any time
subject to the Lien of the  Indenture,  to subject to the Lien of the  Indenture
any  additional  property,  to add one or more  covenants  of the Company and to
establish the terms of Securities of any series as  contemplated  by Section 201
of the Original Indenture;

        WHEREAS,  the Company now desires to correct the  description of certain
property  subject to the Lien of the Indenture,  to subject  certain  additional
property to the Lien of the  Indenture,  to create a third series of  Securities
and to add  to the  covenants  contained  in the  Supplemented  Indenture  to be
observed by the Company;

         WHEREAS,  the  execution  and  delivery  by the  Company of this Second
Supplemental  Indenture,  and the terms of the third series of Securities,  have
been duly authorized by the Company as provided in the Supplemented Indenture;

                                      -1-


         WHEREAS,  Section  1702 of the  Original  Indenture  provides  that the
Company and the Trustee may,  with the consent of the Holders of not less than a
majority in aggregate  principal  amount of the  Outstanding  Securities  of any
series so affected,  amend or modify any of the  covenants  or other  provisions
contained in the Supplemented Indenture;

    WHEREAS,  the amendments and modifications to the Supplemented  Indenture as
set forth in this Second Supplemental  Indenture have been consented to by the
Holder of a majority in  aggregate  principal  amount of the  Securities  of the
Second Series,  as evidenced by a consent  attached to this Second  Supplemental
Indenture;

         NOW, THEREFORE, THIS SECOND SUPPLEMENTAL INDENTURE WITNESSETH, that, in
consideration  of the premises  and of Ten Dollars  ($10) to it duly paid by the
Trustee at or before the  ensealing  and  delivery of this  Second  Supplemental
Indenture, the receipt whereof is hereby acknowledged, and to secure the payment
of the principal of and interest on the  Securities  and the  performance of the
covenants in the  Indenture  and herein  contained  and to declare the terms and
conditions on which the  Securities  are secured,  and in  consideration  of the
premises  and of the  purchase  of the  Securities  by the Holder  thereof,  the
Company by these presents does grant,  bargain,  sell, alien,  remise,  release,
convey, assign, transfer, mortgage, hypothecate, pledge, set over and confirm to
the  Trustee,  and grant a security  interest in, all of the Trust  Estate,  and
including  those parcels of the land described on Exhibit B attached  hereto and
made a part hereof,  together with all of the buildings,  improvements,  plants,
systems,  works,  structures,   water,  sewer  and  other  property,  pipelines,
conduits,  meters,  machinery,   materials,  supplies,   implements,   stations,
substations,  equipment,  instruments,  house and structure  connections and all
other appliances,  apparatus,  fixtures,  fittings and equipment of every nature
and kind  whatsoever,  pertaining to or useful in the operation of the Company's
utility  business,  which is placed  upon or used in  connection  with such real
property.

         TO HAVE AND TO HOLD all said  Trust  Estate  unto the  Trustee  and its
successors and assigns forever.

         SUBJECT,  HOWEVER,  to Permitted Liens and, to the extent  permitted by
Section 704 of the Original Indenture, as to property hereafter acquired,  Prior
Liens existing on the date of acquisition or purchase money mortgages.

         BUT IN TRUST,  NEVERTHELESS,  for the same  purposes  and upon the same
terms,  trusts and  conditions  and  subject to and with the same  provisos  and
covenants  as  are  set  forth  in  the  Supplemented  Indenture,   this  Second
Supplemental Indenture being supplemental thereto.

         AND IT IS HEREBY COVENANTED by the Company that all terms,  conditions,
provisos, covenants and provisions contained in the Supplemented Indenture shall
affect and apply to the Trust Estate and to the estate, rights,  obligations and
duties of the Company and the  Trustee and the  beneficiaries  of the trust with
respect to said  property,  and to the Trustee and its  successors as Trustee of
said  property in the same  manner and with the same effect as if said  property
had been owned by the Company at the time of the execution of the Indenture, and
had been  specifically  and at length described in and conveyed to said Trustee,
by the Indenture as a part of the property therein stated to be conveyed.

         The  Company  further  covenants  and  agrees to and with the  Trustee,
and its successors in said trust under the Indenture, as follows:

                                      -2-



                                  ARTICLE FIRST

                             Amendment to Indenture

SECTION 1.01. Confirmation of Waivers.

         The   requirements  of  Section  3.09(B)  of  the  First   Supplemental
Indenture,  pertaining to the Marco Island System Assets,  have been waived with
the consent of CoBank, as Holder of all of the Securities  Outstanding under the
Indenture,  and such Marco Island  System  Assets shall  continue to  constitute
Excepted  Property,  as set forth in paragraph K of the Excepted Property Clause
contained in the Original Indenture.

SECTION 1.02. Correction of Legal Descriptions - Original Indenture.

         Exhibit A attached to and incorporated  into the Original  Indenture is
hereby  corrected and revised as set forth on Exhibit C attached hereto and made
a part  hereof;  provided,  however,  attachment  of such  revised  Exhibit A is
intended only to correct certain  typographical errors contained in the original
Exhibit A attached to the Original  Indenture  and is not intended to impair the
operation or effect of any previously  granted  partial  release with respect to
any property identified or referred to therein.

SECTION 1.03. Amendments to Original Indenture and First Supplemental Indenture.


         (A) All  references  in the First  Supplemental  Indenture,  including,
without  limitation,  the  reference in  Section 2.61  thereof,  to "8.73%" are
hereby amended to read "8.53%."

         (B)  The  references  in  Section  2.02(B)  of the  First  Supplemental
Indenture to "March 31, 1996" is hereby amended to read "July 31, 2000."

         (C) Paragraphs J and L of the Excepted  Property Clause of the Original
Indenture are hereby deleted in their entireties.

         (D) With the  exception  of the  amendments  to the First  Supplemental
Indenture  and the  Original  Indenture  as  expressly  set forth in this Second
Supplemental Indenture,  the Company hereby confirms that the First Supplemental
Indenture and the Original  Indenture remain in full force and effect,  and that
there has been no  novation  of, and that the  execution  and  delivery  of this
Second   Supplemental   Indenture  shall  not  constitute  a  novation  of,  the
indebtedness evidenced by the Securities of the Second Series.

                                 ARTICLE SECOND

                         Securities of the Third Series

SECTION 2.01. Description of Series.

         There shall be a series of  Securities  designated  '8.137%  Series due
July 31, 2022" (herein  sometimes  referred to as the  "Securities  of the Third
Series"),  each of which shall also bear the  descriptive  title "First Mortgage
Bond",  and the  form  thereof,  which  shall  be  established  in an  Officer's
Certificate as provided in the Indenture, shall contain suitable provisions with
respect to the matters  hereinafter  in this Article  specified.  The  aggregate
principal  amount of Securities  of the Third Series which may be  authenticated
and  delivered   under  the   Indenture  is  limited  to  Ten  Million   Dollars
($10,000,000.00), except as provided in Sections 205 and 206

                                      -3-




of the Original  Indenture.  Securities of the Third Series shall mature on July
31, 2022 and shall be issued as fully registered  Securities in denominations of
One Thousand Dollars and, at the option of the Company, in any integral multiple
or  multiples  thereof  (the  exercise  of such  option to be  evidenced  by the
execution and delivery thereof); they shall bear interest at the rate of 8.137%
per annum,  payable on July 3 1, 1997 for the period from March 31, 1997 to July
31, 1997, and  semi-annually  on January 31 and July 31 of each year  thereafter
until  Maturity;  the principal of,  premium,  if any, and interest on each said
Security  to be  payable  at the  office  or agency of the  Company  in  Apopka,
Florida, in such coin or currency of the United States of America as at the time
of payment is legal tender for public and private debts. Securities of the Third
Series shall be dated as in the Indenture  provided.  Interest on the Securities
of the Third  Series  shall be computed on the actual  number of days elapsed on
the basis of a year  consisting of 360 days. If the Company shall default in the
payment of the  principal  of, or premium or  interest  on, any  Security of the
Third Series,  the Company shall pay to the Holder of such Security such overdue
principal, premium or interest, together with interest on such overdue principal
and (to the extent  permitted by law) on such overdue premium or interest at the
rate  borne by such  Security  immediately  prior to such  default  plus two per
centum (2%) per annum.

         The Regular Record Date referred to in Section 207 of the Indenture for
the payment of the interest on the Securities of the Third Series payable on any
Interest  Payment  Date  shall be the first  Business  Day next  preceding  such
Interest Payment Date.

         The Company  shall be exempt from filing the Cash Flow  Certificate  
provided  in  Section  301(d) of the  Original  Indenture  with  respect  to the
issuance of Securities of the Third Series.

SECTION 2.02. Optional Redemption of Securities of the Third Series.

         (I)  Securities of the Third Series shall be redeemable on any Business
Day,  at the  option  of the  Company,  in whole or in part in  accordance  with
Section 903 of the Original Indenture from time to time, prior to maturity, upon
notice  delivered to each Holder at its last  address  appearing on the Security
Register not less than one Business Day prior to the date fixed for  redemption,
at a Redemption Price ("Third Series General  Redemption Price") (expressed as a
percentage of the principal  amount of the  Securities to be redeemed)  equal to
the  sum of (i)  one  hundred  per  centum  (100%)  plus  (ii) a  "Third  Series
Prepayment  Surcharge" calculated as hereinafter provided, in each case together
with  accrued  interest  to the date  fixed  for  redemption.  For  purposes  of
calculating  the  Third  Series  General  Redemption  Price,  the  Third  Series
Prepayment Surcharge shall be calculated as follows:

               (A) Determine the difference between: (1) eight and 137/1000 per 
               centum (8.137%) minus (2) the Discount Rate, as hereinafter 
               defined, as of the Redemption Date.

               (B) Add one half (1/2) of one per centum (1%) to such difference
               (such that the minimum  result  shall at all times be 1/2 of 1% 
               if the  redemption  occurs prior to July 31,  2000;  thereafter, 
               no amount shall be added in this step (B) provided that, in any 
               event, the minimum result shall be at least zero).

               (C) Divide the result determined in (B) above by 2.

               (D) For each semi-annual period or portion thereof during which 
               the principal amount redeemed was scheduled to have been 
               Outstanding,  multiply the amount described in (C) above by the 
               portion of the principal  amount redeemed that was scheduled to
               have been Outstanding on the last day of such  semi-annual 
               period (such that there is a calculation for each semi-annual

                                      -4-



               period  during which the  principal amount redeemed was scheduled
               to have been Outstanding).

               (E) Determine the present value of each  semi-annual  calculation
               made under (D) above  based upon the scheduled time that interest
               on the  principal  amount redeemed  would have been  payable and
               the  Discount  Rate as of the  Redemption Date.
               
               (F) Add all of the calculations made under (E) above. The result
               shall be the Third Series Prepayment Surcharge.

         Unless  otherwise  agreed  with  a  majority  of  the  Holders  of  the
Securities of the Third Series to be Outstanding  after a redemption  under this
Section,  the Securities redeemed under this Section may not be used as a credit
for the  redemption  of  Securities  provided for in Section 2.03 of this Second
Supplemental Indenture.

         (II) A notice  containing  the  calculation of the Third Series General
Redemption  Price shall be prepared by the Company and  delivered to the Trustee
and the  Holders of the  Securities  of the Third  Series to be  redeemed on the
Business Day next preceding the Redemption  Date. The  calculation  set forth in
such  notice  shall be final  unless the Holders of the  Securities  so redeemed
notify the  Company and the  Trustee of an error in such calculations within 30
days after notice of such calculation.  If it is determined that the Company has
made an error in such  calculation  and the Company pays the  difference to such
Holders promptly after such determination,  then the Company shall not be deemed
to be in  default  under  the  Indenture  by  reason  of  late  payment  of such
difference.

          (III) As pertains to  Securities  of the Third  Series,  the "Discount
Rate" shall mean an interest rate  determined by adding to the yield on treasury
bonds having  maturities  equal to the weighted  average life to maturity of the
Securities to be redeemed,  determined as necessary by interpolation of treasury
bonds having the next longer and next shorter maturities  ("Treasury Yield"), as
reported on the "MMKS"  Reuters  monitor  screen for the Business Day prior to 
the Redemption Date for such Securities, the following:

               (A) the  estimated  spread  of Farm  Credit  Securities  over the
               Treasury Yield for such day, as reported in a Farm Credit Funding
               Corporation Interest Rate Summary report, and

               (B) the  estimated  dealer  concession,  obtained by a polling of
               Farm Credit Funding  Corporation dealers on the Business Day next
               preceding the Redemption Date, for issuing Farm Credit Securities
               having  a  weighted  average  life  equal to the  number  of days
               between the  Redemption  Date and Maturity for  Securities of the
               Third Series to be redeemed.

       In the event any fact required for such calculation is not available, the
computation  of  Discount  Rate  shall  be made  on the  basis  of a  reasonably
equivalent method of determination.

SECTION 2.03. Sinking Fund for Securities of the Third Series.

      So long as any  Securities  of the Third Series shall remain  Outstanding,
the Company shall redeem the principal  thereof in accordance with the following
schedule,  commencing  on July 31,  1997 and  semi-annually  on or  before  each
January 31 and July 31 thereafter, through and including July 31, 2022:

July 31, 1997        $ 61,241.65           January 31, 1998          $ 63,733.27
July 31, 1998        $ 66,326.25           January 31, 1999          $ 69,024.74

                                      -5-




July 31,  1999       $ 71,833.01           January 31, 2000          $ 74,755.54
July 31,  2000       $ 77,796.96           January 31, 2001          $ 80,962.13
July 31,  2001       $ 84,256.08           January 31, 2002          $ 87,684.04
July 31,  2002       $ 91,251.46           January 31, 2003          $ 94,964.03
July 31,  2003       $ 98,827.64           January 31, 2004          $102,848.44
July 31,  2004       $107,032.83           January 31, 2005          $111,387.46
July 31,  2005       $115,919.26           January 31, 2006          $120,635.44
July 31,  2006       $125,543.49           January 31, 2007          $130,651.23
July 31,  2007       $135,966.77           January 31, 2008          $141,498.58
July 31,  2008       $147,255.45           January 31, 2009          $153,246.54
July 31,  2009       $159,481.37           January 31, 2010          $165,969.87
July 31,  2010       $172,722.36           January 31, 2011          $179,749.56
July 31,  2011       $187,062.68           January 31, 2012          $194,673.32
July 31,  2012       $202,593.60           January 31, 2013          $210,836.13
July 31,  2013       $219,433.99           January 31, 2014          $228,340.85
July 31,  2014       $237,630.90           January 31, 2015          $247,298.91
July 31,  2015       $257,360.27           January 31, 2016          $267,830.97
July 31,  2016       $278,727.67           January 31, 2017          $290,067.71
July 31,  2017       $301,869.11           January 31, 2018          $314,150.66
July 31,  2018       $326,931.88           January 31, 2019          $340,233.10
July 31,  2019       $354,075.49           January 31, 2020          $368,481.05
July 31,  2020       $383,472.70           January 31, 2021          $399,074.28
July 31,  2021       $415,310.62           January 31, 2022          $432,207.53
July 31,  2022       $449,791.13


       
                                  ARTICLE THIRD

                      Additional Covenants for Third Series

SECTION 3.01. Asset Sale Restrictions for the Third Series.
         
         (A) So long as any  Securities of the Third Series remain  Outstanding,
if the Company  requests the release of Property  Additions  pursuant to Section
1003 or 1004 of the  Original  Indenture  (other  than for  purposes of sales of
property pursuant to or under threat,  reasonably  believed by the Company to be
genuine,  of the  exercise  of a power  of  eminent  domain  or for  tax  exempt
financing  pursuant to Section 1009 of the Original  Indenture),  the  Officer's
Certificate  filed in connection  with such release shall  identify the Property
Additions that are to be so released.

         (B) So long as any  Securities of the Third Series remain  Outstanding,
if the aggregate  amount of Property  Additions  released upon such basis during
any  calendar  year  shall  exceed  ten per  centum  (10%) of the  amount of Net
Property Additions shown in the most recent Property Additions Certificate filed
with the Trustee,  then the Company  shall  promptly  notify the Trustee and, if
there is only one Holder of  Securities  of such Series,  such  Holder;  and the
Company shall within forty-five days thereafter redeem or have otherwise retired
(other than  pursuant to Section  2.03 of this Second  Supplemental  Indenture),
except to the extent  waived by the Holder,  an  aggregate  principal  amount of
Securities  of such  Series  equal to a pro rata  portion  of the amount of such
excess,  such  pro rata  portion  to be  based  upon  the  ratio of (a) the then
Outstanding aggregate principal amount of Securities of the Third Series, to (b)
the then Outstanding aggregate principal amounts of

                                      -6-


Securities of the Second Series and of the Third Series;  provided however, that
to the extent the Holders of the Securities of the Second Series waive any right
of redemption  under Section  4.01(B) of this Second  Supplemental  Indenture as
provided in Section 4.01(D) hereof, an additional principal amount of Securities
of the Third  Series,  in an amount equal to the amount waived by the Holders of
the  Securities  of the Second  Series,  shall be  redeemed  as provided in this
Section 3.01(B), except to the extent waived by the Holders of the Securities of
the Third Series.

         (C) So long as any  Securities of the Third Series remain  Outstanding,
if the aggregate amount of Property  Additions released since March 1, 1993 upon
such  basis  shall  exceed  twenty  five per  centum (25%) of the amount of Net
Property Additions shown in the most recent Property Additions Certificate filed
with the Trustee,  then the Company  shall  promptly  notify the Trustee and, if
there is only one Holder of  Securities  of such Series,  such  Holder;  and the
Company  shall  within  forty-five  days  thereafter  redeem or have  other-wise
retired  (other  than  pursuant  to  Section  2.03 of this  Second  Supplemental
Indenture),  except to the  extent  waived,  an  aggregate  principal  amount of
Securities  of such  Series  equal to a pro rata  portion  of the amount of such
excess,  such  pro rata  portion  to be  based  upon  the  ratio of (a) the then
Outstanding aggregate principal amount of Securities of the Third Series, to (b)
the then  Outstanding  aggregate  principal  amounts of Securities of the Second
Series  and of the Third  Series;  provided,  however,  that to the  extent  the
Holders of the  Securities  of the Second  Series waive any right of  redemption
under  Section  4.01(C) of this  Second  Supplemental  Indenture  as provided in
Section  4.01(D)  hereof,  an additional  principal  amount of Securities of the
Third  Series,  in an amount  equal to the amount  waived by the  Holders of the
Securities of the Second  Series,  shall be redeemed as provided in this Section
3.01(C),  except to the extent  waived by the Holders of the  Securities  of the
Third Series.
           
         (D) With respect to the redemptions described in paragraphs (B) and (C)
above, the Company shall receive a credit for any Securities of the Third Series
(excluding   Securities  redeemed  pursuant  to  Section  2.03  of  this  Second
Supplemental  Indenture)  retired prior to the respective  Redemption Date. With
respect to the  redemptions  described  in  paragraphs  (B) and (C)  above,  the
Redemption  Price  shall be the Third  Series  General  Redemption  Price,  plus
interest accrued to the Redemption Date. Such redemption shall be prorated among
Holders of  Securities  of the Third  Series  except to the extent  waived;  any
Holder may waive its right to such  redemption by delivering a written waiver to
the Trustee,  in such form as the Trustee shall deem acceptable,  with a copy to
the Company, within ten days after the date of such notice of redemption.

         (E)  Unless  otherwise  agreed  with a majority  of the  Holders of the
Securities of the Third Series to be Outstanding  after a redemption  under this
Section,  the Securities redeemed under this Section may not be used as a credit
for the  redemption  of  Securities  provided for in Section 2.03 of this Second
Supplemental Indenture.

SECTION 3.02. Ownership by Minnesota Power & Light Company.

         So long as any  Securities of the Third Series remain  Outstanding,  if
the  Company's  entire  common  stock  shall  cease  to be  owned,  directly  or
indirectly,  by Minnesota Power & Light Company, then the Company shall promptly
notify  the  Trustee  and,  if there is only one  Holder of  Securities  of such
Series, such Holder; and the Company shall redeem, within ninety days thereafter
and upon at least thirty days' notice, all of the Securities of such Series then
Outstanding at the Third Series General  Redemption  Price,  respectively,  plus
interest accrued to the Redemption Date. Any Holder of such Series may waive its
right to such redemption by delivering a written waiver to the Trustee,  in such
form as the Trustee shall deem  acceptable,  with a copy to the Company,  within
ten days after the date of such notice of redemption.

                                      -7-


SECTION 3.03. Additional Debt Covenants.

         (A) So  long  as  any  Securities  of the  Third  Series  shall  remain
Outstanding,  the Company shall file a Cash Flow Certificate with the Trustee on
or before  March 31 of each  calendar  year  after 1996 for the period of twelve
consecutive  calendar  months ending December 31 of the  immediately  preceding
calendar  year and stating the ratio of its Total Debt divided by its Cash Flow,
determined in  accordance  with  generally  accepted  accounting  principles
existing as of the date of the First  Supplemental  Indenture,  as shown by such
certificate ("Annual Total Debt/Cash Flow Ratio"). If the annual Total Debt/Cash
Flow Ratio  shall  exceed the  maximums  specified  below for the  corresponding
period:

          Twelve Month
          Period Ending                         Maximum Total Debt/
           December 31,                               Cash Flow Ratio
          -------------                               ---------------

          1996 and thereafter                              15:1

then the Company  shall  promptly  notify the Trustee  and, if there is only one
Holder of Securities of such Series,  such Holder; and the Company shall redeem,
within  ninety  days  thereafter  and  upon at least  thirty  days'  notice,  an
aggregate  principal  amount of the  Securities of such Series then  Outstanding
equal to a pro rata portion of the amount  sufficient  to cause the Annual Total
Debt/Cash Flow Ratio to equal the appropriate maximum,  such pro rata portion to
be based upon the ratio of (a) the then Outstanding  aggregate  principal amount
of  Securities  of the  Third  Series  to (b)  the  then  Outstanding  aggregate
principal  amounts  of the  Securities  of the  Second  Series  and of the Third
Series;  provided,  however, that to the extent the Holders of the Securities of
the Second  Series waive any right of redemption  under Section  4.03(A) of this
Second Supplemental Indenture as provided in such Section 4.03(A), an additional
principal  amount of Securities  of the Third Series,  in an amount equal to the
amount waived by the Holders of the  Securities of the Second  Series,  shall be
redeemed as provided in this Section 3.03(A), except to the extent waived by the
Holders of the Securities of the Third Series. The Redemption Price shall be the
Third Series General  Redemption  Price, plus interest accrued to the Redemption
Date.  The  Holders of a majority  of the  Securities  of the Third  Series then
Outstanding  may waive such  redemption  by  delivering a written  waiver to the
Trustee,  in such form as the Trustee shall deem acceptable,  with a copy to the
Company, within ten days after the date of such notice of redemption.

         (B) So  long  as  any  Securities  of the  Third  Series  shall  remain
Outstanding,  the Company shall file with the Trustee,  on or before March 31 of
each calendar year, an Accountant's Certificate showing as of December 31 of the
immediately  preceding  calendar  year (1) the  aggregate  principal  amount  of
Securities then  Outstanding  and (2) the net book value of property,  plant and
equipment,   determined  in  accordance  with  generally   accepted   accounting
principles  existing as of the date of the First Supplemental  Indenture,  which
constitute Property Additions.  If such aggregate principal amount of Securities
then  Outstanding  exceeds  sixty per centum (60%) of the net book value of such
property, plant and equipment then the Company shall promptly notify the Trustee
and, if there is only one Holder of Securities of the Third Series, such Holder;
and the Company shall redeem,  within ninety days  thereafter  and upon at least
thirty days' notice,  a principal  amount of the  Securities of such Series then
Outstanding  equal to a pro rata  portion of the amount  necessary  to cause the
aggregate  principal  amount of Securities  then  Outstanding to equal sixty per
centum (60%) of the net book value of such property,  plant and equipment,  such
pro rata  portion  to be  based  upon  the  ratio  of (a) the  then  Outstanding
aggregate  principal  amount of Securities of the Third Series,  to (b) the then
Outstanding  aggregate  principal amounts of Securities of the Second Series and
of the Third Series;  provided,  however,  that to the extent the Holders of the
Securities  of the Second  Series waive any right of  redemption  under  Section
4.03(B) of this  Second  Supplemental  Indenture  as  provided  in such  Section
4.03(B), an additional principal amount of Securities of the

                                      -8-



Third  Series,  in an amount  equal to the amount  waived by the  Holders of the
Securities of the Second  Series,  shall be redeemed as provided in this Section
3.03(B),  except to the extent  waived by the Holders of the  Securities  of the
Third Series.  The Redemption Price shall be the Third Series General Redemption
Price,  plus interest  accrued to the Redemption Date. The Holders of a majority
of the Securities of the Third Series then Outstanding may waive such redemption
by delivering a written waiver to the Trustee, in such form as the Trustee shall
deem acceptable,  with a copy to the Company,  within ten days after the date of
such notice of redemption.

         (C) So  long  as  any  Securities  of the  Third  Series  shall  remain
Outstanding,  the Company shall file with the Trustee,  on or before March 31 of
each calendar year, an Accountant's Certificate showing as of December 31 of the
immediately  preceding calendar year (1) the Total Debt of the Company,  and (2)
the Company's  Capitalization,  determined in accordance with generally accepted
accounting  principles  existing  as of  the  date  of  the  First  Supplemental
Indenture:  If  such  Total  Debt  exceeds  sixty-five  per  centum  (65%)  of
Capitalization, then the Company shall promptly notify the Trustee and, if there
is only one Holder of  Securities of such Series,  such Holder;  and the Company
shall  redeem,  within  ninety days  thereafter  and upon at least  thirty days'
notice,  a principal  amount of the  Securities of such Series then  Outstanding
equal to a pro rata portion of the amount necessary to cause Total Debt to equal
not more than  sixty-five  per centum (65%) of  Capitalization,  determined  in
accordance with generally accepted accounting principles existing as of the date
of the First Supplemental Indenture,  such pro rata portion to be based upon the
ratio of (a) the then  Outstanding  aggregate  principal amount of Securities of
the Third Series,  to (b) the then Outstanding  aggregate  principal  amounts of
Securities of the Second Series and of the Third Series; provided, however, that
to the extent the Holders of the Securities of the Second Series waive any right
of redemption  under Section  4.03(C) of this Second  Supplemental  Indenture as
provided in such Section 4.03(C),  an additional  principal amount of Securities
of the Third  Series,  in an amount equal to the amount waived by the Holders of
the  Securities  of the Second  Series,  shall be  redeemed  as provided in this
Section 3.03(C), except to the extent waived by the Holders of the Securities of
the  Third  Series.  The  Redemption  Price  shall be the Third  Series  General
Redemption Price, plus interest accrued to the Redemption Date. The Holders of a
majority of the Securities of the Third Series then  Outstanding  may waive such
redemption  by delivering a written  waiver to the Trustee,  in such form as the
Trustee shall deem acceptable, with a copy to the Company, within ten days after
the date of such notice of redemption.

        (D) So  long  as  any  Securities  of  the  Third  Series  shall  remain
Outstanding,  the  Holders of a majority of the  Securities  of such Series then
Outstanding  may,  from time to time but not more than once during any  calendar
year,  upon thirty days notice,  request that the Company file with the Trustee,
as of the end of any calendar month other than December  within sixty days after
the end of such month,  the Cash Flow  Certificate  provided in Section  3.03(A)
hereof and the Accountant's Certificates provided in Section 3.03(B) and 3.03(C)
of this Second  Supplemental  Indenture.  The same redemption  provisions  shall
apply as if such Cash Flow  Certificate and  Accountant's  Certificates had been
delivered  pursuant to such Section  3.03(A),  3.03(B) or 3.03(C) of this Second
Supplemental  Indenture,  using with respect to Section  3.03(A) the maximum for
the period ending on the December 31 next preceding such calendar month.

        (E)  Unless  otherwise  agreed  by a  majority  of  the  Holders  of the
Securities of the Third Series to be Outstanding  after a redemption  under this
Section 3.03, the Securities redeemed under this Section 3.03 may not be used as
a credit for the  redemption of Securities  provided for in Section 2.03 of this
Second Supplemental Indenture.

                                      -9-


SECTION 3.04. Restricted Payments.

         So long as any Securities of the Third Series remain  Outstanding,  the
Company  shall not  declare or pay any  Restricted  Payments  unless the Company
files an  Accountant's  Certificate  with the Trustee  and, if there is only one
Holder of Securities of the Third  Series,  sends a copy to such Holder,  within
thirty days prior to such  declaration or payment stating that (A) the amount of
such payment shall not exceed  cumulative  net  additions to or deductions  from
Surplus,  determined in accordance with generally accepted accounting principles
existing  as of the  date of this  Second  Supplemental  Indenture,  made  after
December 31, 1992 (excluding any gains on sale of Property  Additions during the
immediately  preceding 12 months in excess of twenty per centum (20%) of the net
additions to Surplus made during such 12 month period);  and (B) that after such
payment  Capital plus Surplus shall equal at least  thirty-five per centum (35%)
of Capitalization,  determined in accordance with generally accepted  accounting
principles existing as of the date of the First Supplemental Indenture.

SECTION 3.05. Redemption Upon Taking of Property by Eminent Domain, etc.

         So long as any Securities of the Third Series shall remain Outstanding,
any Officer's  Certificate provided under Section 1006 of the Original Indenture
shall also state the net book value of the Mortgaged  Property described therein
as taken or sold,  and shall  also  state the net book  value of such  Mortgaged
Property that does not constitute Property Additions.  Notwithstanding  anything
to the contrary contained in Section 1006 of the Original Indenture,  should the
aggregate  net book value of  Mortgaged  Property  taken by the  exercise of the
power of  eminent  domain or sold to an entity  possessing  the power of eminent
domain, or to its designee,  under a threat,  reasonably believed by the Company
to be genuine,  to exercise the same,  be in excess of Fifteen  Million  Dollars
($15,000,000),  the Company shall  redeem,  within ninety days of such taking or
sale and upon at least thirty days' notice, or have otherwise retired, except to
the extent waived,  an aggregate  principal  amount of Securities of such Series
then Outstanding equal to an amount determined pursuant to the next sentence, at
the Redemption  Price of par plus interest  accrued to the Redemption  Date. The
principal  amount of Securities  of the Third Series to be redeemed  pursuant to
this Section 3.05 shall be calculated  by dividing (1) the  aggregate  amount of
Property  Additions  so taken or sold plus the  aggregate  net book value of all
Mortgaged  Property so taken or sold which are not Property Additions by (2) the
amount of Net Property  Additions  shown on the most recent  Property  Additions
Certificate  filed with the Trustee and multiplying  such ratio by the aggregate
principal  amount of  Securities  of such  Series  then  Outstanding;  provided,
however,  that to the extent the Holders of the  Securities of the Second Series
waive any right of  redemption  under  Section 4.05 of this Second  Supplemental
Indenture as provided in such Section 4.05, an  additional  principal  amount of
Securities  of the Third  Series  shall be redeemed as provided in this  Section
3.05 in an amount equal to the amount waived by the Holders of the Securities of
the Second Series,  except to the extent waived by the Holders of the Securities
of the Third  Series.  Such  redemption  shall be  prorated  among  Holders  of
Securities of such Series except to the extent waived;  any Holder may waive its
right to such redemption by delivering a written waiver to the Trustee,  in such
form as the Trustee shall deem  acceptable,  with a copy to the Company,  within
ten days after the date of such  notice of  redemption;  such  waiver  shall not
cause a recalculation of the proration.

SECTION 3.06. Maintenance of Business.

         So long as any  Securities of the Third Series remain  Outstanding,  if
the Company ceases to continue  substantially in the business of providing water
and waste water utility service in the State of Florida,  then the Company shall
promptly  notify the Trustee and, if there is only one Holder of  Securities  of
such Series, such Holder; and the Company shall redeem,  within ninety days and
upon at least  thirty days  notice,  all of the  Securities  of such Series then
Outstanding at the Third Series General  Redemption Price, plus interest accrued
to the  Redemption  Date.  Any Holder may waive its right to such  redemption by
delivering a written waiver

                                      -10-



to the Trustee,  in such form as the Trustee shall deem acceptable,  with a copy
to the Company, within ten days after the date of such notice of redemption.

SECTION 3.07. Return of Redemption Moneys upon Waiver.

         Upon  receipt of any waiver of  redemption  by any Holder,  the Trustee
shall return to the Company the  redemption  money,  if any, held by the Trustee
for the redemption of such Holder's Securities.

SECTION 3.08. Special Merger Provisions.

         So long as any Securities of the Third Series remain  Outstanding,  the
Company- shall not merge or  consolidate  with another entity unless the Company
shall  have  filed  with the  Trustee,  and,  if there  is only  one  Holder  of
Securities of such Series,  such Holder, an Officer's  Certificate  stating that
(1) the Company or an entity directly or indirectly owned one hundred per centum
(100%) by  Minnesota  Power  &  Light  Company  shall  be the  continuing  and
surviving  corporation and, (2) after such merger or consolidation,  there shall
exist no Event of  Default or event  which,  with the lapse of time or giving of
notice, or both, would constitute an Event of Default,  and the Company shall be
able to issue at least One Dollar ($1) of  Securities  under the  provisions  of
Section 401 or 501 of the Indenture, in each case, using a Cash Flow Certificate
stating  an  Annual  Total  Debt/Cash  Flow  Ratio not to  exceed  the  maximums
specified in Section  3.03(A) hereof (using the maximum for the period ending on
the  December  31  next  preceding  such  merger)  rather  than  the  Cash  Flow
Certificate provided in Section 301(d) of the Original Indenture.

SECTION 3.09. Bond Purchase Agreement.

         So long as  CoBank  shall be the sole  owner of all  Securities  of the
Third Series then  Outstanding,  the Company shall redeem,  within ten days, an
aggregate principal amount of Securities of such Series, the redemption of which
is demanded,  in a certificate,  signed by the President,  any Vice President or
any Assistant Vice President of CoBank,  stating that CoBank is entitled to such
redemption under the Bond Purchase Agreement dated March 31, 1997 between CoBank
and the Company,  describing  the event giving CoBank such right of  redemption,
and stating  that such  redemption  is  required by terms of such Bond  Purchase
Agreement.  The Redemption  Price shall be the Third Series  General  Redemption
Price, plus interest accrued to the Redemption Date.

SECTION 3.10. Property Additions Certificates.

         So long as any Securities of the Third Series shall remain Outstanding,
the  Company  shall file a Property  Additions  Certificate  with the Trustee at
least once during each calendar year.

SECTION 3.11. Amendment to Indenture; Acceleration.

         So long as the  aggregate  principal  amount of Securities of the Third
Series then  Outstanding,  combined,  if and only if the Holder of a majority in
aggregate   principal  amount  of  the  Securities  of  the  Third  Series  then
Outstanding  is also the Holder of a majority in aggregate  principal  amount of
the  Securities  of the  Second  Series  then  Outstanding,  with the  aggregate
principal  amount of the  Securities  of the  Second  Series  then  Outstanding,
exceeds  twenty-five  per centum  (25%) of the  aggregate  principal  amount of
Securities of all series then  Outstanding,  the words  "twenty-five per centum
(25%)" shall be  substituted  for the words  "thirty-three  and  one-third  per
centum  (33  1/3%)"  in  Section  1102 of the  Original  Indenture.  In case any
Securities of the Third

                                      -11-



Series are paid by reason of a declaration of  acceleration  pursuant to Section
1102 of the  Original  Indenture,  the Company  shall pay to the Holders of such
Securities a premium equal to the Prepayment  Surcharge,  calculated as provided
in Section 2.02 of this Second Supplemental  Indenture with respect to the Third
Series  multiplied  by the  aggregate  principal  amount of such  Securities  so
accelerated,  provided  that the  payment  of such  premium  does not render the
Company insolvent.  If the aggregate principal amount of Securities of the Third
Series then  Outstanding,  combined,  if and only if the Holder of a majority in
aggregate   principal  amount  of  the  Securities  of  the  Third  Series  then
Outstanding  is also the Holder of a majority in aggregate  principal  amount of
the  Securities  of the  Second  Series  then  Outstanding,  with the  aggregate
principal  amount of the  Securities  of the  Second  Series  then  Outstanding,
exceeds  twenty-five  per  centum  (25%) of the  aggregate  principal  amount of
Securities of all series then Outstanding and an Event of Default  shall exist,
then the Holders of the Securities of the Third Series may demand the redemption
of such Securities of the Third Series held by them upon ten days written notice
to the Company and the Trustee.  The Redemption  Price shall be the Third Series
General Redemption Price, respectively,  plus interest accrued to the Redemption
Date.

SECTION 3.12. Redemptions on a Business Day

         In the event any Redemption  Date for a redemption  required by Section
3.03 hereof shall not be a Business Day,  interest on the principal  amount then
due shall  accrue to and be paid on the next  Business  Day;  provided  that the
Company  may, at its option,  upon ten (10) days prior notice to the Trustee and
the  Holders,  satisfy a  redemption  required  by  Section  3.03  hereof on the
Business Day prior to the applicable Redemption Date at a Redemption Price equal
to par plus interest  accrued to such prior  Business Day. Any other  Redemption
Date for Securities of the Third Series shall be on a Business Day.

SECTION 3.13. Amendment or Waiver of Covenants.

         The  provisions of this Article Third may be waived or amended,  at the
request of the  Company,  with the written  consent of the Holders of at least a
majority of the aggregate principal amount of the Securities of the Third Series
then Outstanding. So long as the aggregate principal amount of Securities of the
Third Series then Outstanding, combined, if and only if the Holder of a majority
in  aggregate  principal  amount  of the  Securities  of the Third  Series  then
Outstanding  is also the Holder of a majority in aggregate  principal  amount of
the  Securities  of the  Second  Series  then  Outstanding,  with the  aggregate
principal  amount of the  Securities  of the  Second  Series  then  Outstanding,
exceeds  twenty-five  per centum  (25%) of the  aggregate  principal  amount of
Securities of all series then Outstanding,  the provisions of this Article Third
may not be waived nor amended  without the written  consent of the Holders of at
least a majority of the  aggregate  principal  amount of Securities of the Third
Series then Outstanding, except as otherwise specifically provided herein.

                                 ARTICLE FOURTH

                       Amended Covenants for Second Series

SECTION 4.01. Asset Sale Restrictions for the Second Series.

         (A) So long as any Securities of the Second Series remain  Outstanding,
if the Company  requests the release of Property  Additions  pursuant to Section
1003 or 1004 of the  Original  Indenture  (other  than for  purposes of sales of
property pursuant to or under threat,  reasonably  believed by the Company to be
genuine,  of the  exercise  of a power  of  eminent  domain  or for  tax  exempt
financing pursuant to Section 1009 of the

                                      -12-



Original  Indenture),  the Officer's  Certificate  filed in connection with such
release shall identify the Property Additions that are to be so released.

         (B) So long as any Securities of the Second Series remain  Outstanding,
if the aggregate amount of Property Additions released since March 31, 1993 upon
such basis  during any  calendar  year shall exceed ten per centum (10%) of the
amount of Net Property  Additions  shown in the most recent  Property  Additions
Certificate  filed with the Trustee,  then the Company shall promptly notify the
Trustee  and, if there is only one Holder of  Securities  of such  Series,  such
Holder;  and the Company shall within  forty-five days thereafter redeem or have
otherwise retired (other than pursuant to Section 2.03 of the First Supplemental
Indenture),  except to the extent waived by the Holder,  an aggregate  principal
amount of Securities of such Series equal to a pro rata portion of the amount of
such  excess,  such pro rata  portion to be based upon the ratio of (a) the then
Outstanding  aggregate  principal amount of Securities of the Second Series,  to
(b) the then Outstanding aggregate principal amounts of Securities of the Second
Series  and of the Third  Series;  provided,  however,  that to the  extent  the
Holders of the  Securities  of the Third  Series  waive any right of  redemption
under Section 3.01(B) of this Second Supplemental  Indenture as provided in such
Section  3.01(D),  an  additional  principal  amount of Securities of the Second
Series, in an amount equal to the amount waived by the Holders of the Securities
of the Third  Series,  shall be redeemed as  provided in this  Section  4.01(B),
except to the  extent  waived by the  Holders  of the  Securities  of the Second
Series.

         (C) So long as any Securities of the Second Series remain  Outstanding,
if the  aggregate  amount of Property  Additions  released upon such basis shall
exceed  twenty  five per centum (25%) of the amount of Net  Property  Additions
shown in the most recent Property Additions  Certificate filed with the Trustee,
then the Company  shall  promptly  notify the  Trustee  and, if there is only on
Holder of Securities of such Series,  such Holder;  and the Company shall within
forty-five days thereafter redeem or have otherwise retired (other than pursuant
to  Section  2.03 of the First  Supplemental  Indenture),  except to the  extent
waived,  an aggregate  principal  amount of Securities of such Series equal to a
pro rata portion of the amount of such excess, such pro rata portion to be based
upon  the  ratio of (a) the  then  Outstanding  aggregate  principal  amount  of
Securities of the Second Series, to (b) the then Outstanding aggregate principal
amounts of Securities  of the Second  Series and of the Third Series;  provided,
however,  that to the extent the Holders of the  Securities  of the Third Series
waive any right of redemption under Section 3.01(C) of this Second  Supplemental
Indenture as provided in such Section 3.01(D), an additional principal amount of
Securities  of the Second  Series,  in an amount equal the amount  waived by the
Holders of the Securities of the Third Series,  shall be redeemed as provided in
this  Section  4.01(C),  except  to the  extent  waived  by the  Holders  of the
Securities of the Second Series.

         (D) With respect to the redemptions described in paragraphs (B) and (C)
above,  the  Company  shall  receive a credit for any  Securities  of the Second
Series  (excluding  Securities  redeemed  pursuant to Section  2.03 of the First
Supplemental  Indenture)  retired prior to the respective  Redemption Date. With
respect to the  redemptions  described  in  paragraphs  (B) and (C)  above,  the
Redemption  Price shall be the Second  Series  General  Redemption  Price,  plus
interest accrued to the Redemption Date. Such redemption shall be prorated among
Holders of  Securities of the Second  Series  except to the extent  waived;  any
Holder may waive its right to such  redemption by delivering a written waiver to
the Trustee,  in such form as the Trustee shall deem acceptable,  with a copy to
the Company, within ten days after the date of such notice of redemption.

         (E)  Unless  otherwise  agreed  with a majority  of the  Holders of the
Securities of the Second Series to be Outstanding  after a redemption under this
Section,  the Securities redeemed under this Section may not be used as a credit
for the  redemption  of  Securities  provided  for in Section  2.03 of the First
Supplemental Indenture.

                                      -13-



SECTION 4.02. Ownership by Minnesota Power & Light Company.

         So long as any Securities of the Second Series remain  Outstanding,  if
the  Company's  entire  common  stock  shall  cease  to be  owned,  directly  or
indirectly,  by Minnesota Power & Light Company, then the Company shall promptly
notify the  Trustee  and,  if there is only one Holder of  Securities  of  such
Series, such Holder; and the Company shall redeem, within ninety days thereafter
and upon at least thirty days' notice, all of the Securities of such Series then
Outstanding at the Second Series General  Redemption Price,  respectively,  plus
interest accrued to the Redemption Date. Any Holder of such Series may waive its
right to such redemption by delivering a written waiver to the Trustee,  in such
form as the Trustee shall deem  acceptable,  with a copy to the Company,  within
ten days after the date of such notice of redemption.

SECTION 4.03. Additional Debt Covenants.

         (A) So  long  as any  Securities  of the  Second  Series  shall  remain
Outstanding,  the Company shall file a Cash Flow Certificate with the Trustee on
or before  March 31 of each  calendar  year  after 1996 for the period of twelve
consecutive  calendar  months ending  December 31 of the  immediately  preceding
calendar  year and stating the ratio of its Total Debt divided by its Cash Flow,
determined in accordance with generally accepted accounting  principles existing
as of the date of the First Supplemental Indenture, as shown by such certificate
("Annual Total Debt/Cash Flow Ratio").  If the annual Total Debt/Cash Flow Ratio
shall exceed the maximums specified below for the corresponding period:

               Twelve Month
               Period Ending              Maximum Total Debt/
                December 31,                     Cash Flow Ratio
               -------------                     ---------------

               1996 and thereafter                     15:1

then the Company  shall  promptly  notify the Trustee  and, if there is only one
Holder of Securities of such Series,  such Holder; and the Company shall redeem,
within  ninety  days  thereafter  and  upon at least  thirty  days'  notice,  an
aggregate  principal  amount of the  Securities of such Series then  Outstanding
equal to a pro rata portion of the amount  sufficient to cause the Annual Total
Debt/Cash Flow Ratio to equal the appropriate maximum,  such pro rata portion to
be based upon the ratio of (a) the then Outstanding  aggregate  principal amount
of  Securities  of the  Second  Series,  to (b) the then  Outstanding  aggregate
principal  amounts of  Securities  of the Second Series and of the Third Series;
provided, however, that to the extent the Holders of the Securities of the Third
Series  waive any right of  redemption  under  Section  3.03(A)  of this  Second
Supplemental  Indenture  as  provided in such  Section  3.03(A),  an  additional
principal amount of Securities of the Second Series,  in an amount equal to the
amount  waived by the Holders of the  Securities of the Third Series,  shall be
redeemed as provided in this Section 4.03(A), except to the extent waived by the
Holders of the  Securities of the Second Series.  The Redemption  Price shall be
the Second  Series  General  Redemption  Price,  plus  interest  accrued to the
Redemption  Date.  The  Holders of a majority  of the  Securities  of the Second
Series then Outstanding may waive such redemption by delivering a written waiver
to the Trustee,  in such form as the Trustee shall deem acceptable,  with a copy
to the Company, within ten days after the date of such notice of redemption.

         (B) So  long  as any  Securities  of the  Second  Series  shall  remain
Outstanding,  the Company shall file with the Trustee,  on or before March 31 of
each calendar year, an  Accountant's  Certificate  showing as of December 31 of
the immediately  preceding  calendar year (1) the aggregate principal amount of
Securities then  Outstanding  and (2) the net book value of property,  plant and
equipment, determined in accordance with generally accepted accounting 
principles existing as of the date of the First Supplemental Indenture, which

                                      -14-



constitute Property Additions.  If such aggregate principal amount of Securities
then  Outstanding  exceeds sixty per centum (60%) of the net book value of such
property, plant and equipment then the Company shall promptly notify the Trustee
and,  if there is only one  Holder of  Securities  of the  Second  Series,  such
Holder; and the Company shall redeem,  within ninety days thereafter and upon at
least thirty days' notice,  a principal  amount of the Securities of such Series
then  Outstanding  equal to a pro rata portion of the amount  necessary to cause
the aggregate  principal  amount of Securities then  Outstanding to equal sixty
per centum (60%) of the net book value of such  property,  plant and equipment,
such pro rata  portion  to be based  upon the ratio of (a) the then  Outstanding
aggregate  principal amount of Securities of the Second Series,  to (b) the then
Outstanding  aggregate  principal amounts of Securities of the Second Series and
of the Third Series;  provided,  however,  that to the extent the Holders of the
Securities  of the Third  Series  waive any right of  redemption  under  Section
3.03(B) of this  Second  Supplemental  Indenture  as  provided  in such  Section
3.03(B),  an additional  principal amount of Securities of the Second Series, in
an amount  equal to the amount  waived by the Holders of the  Securities  of the
Third Series,  shall be redeemed as provided in this Section 4.03(B),  except to
the extent  waived by the Holders of the  Securities of the Second  Series.  The
Redemption  Price shall be the Second  Series  General  Redemption  Price,  plus
interest  accrued to the  Redemption  Date.  The  Holders  of a majority  of the
Securities of the Second Series then  Outstanding  may waive such  redemption by
delivering a written  waiver to the Trustee,  in such form as the Trustee  shall
deem acceptable,  with a copy to the Company,  within ten days after the date of
such notice of redemption.

         (C) So  long  as any  Securities  of the  Second  Series  shall  remain
Outstanding,  the Company shall file with the Trustee,  on or before March 31 of
each calendar year, an Accountant's Certificate showing as of December 31 of the
immediately  preceding calendar year (1) the Total Debt of the Company,  and (2)
the Company's  Capitalization,  determined in accordance with generally accepted
accounting  principles  existing  as of  the  date  of  the  First  Supplemental
Indenture.   If  such  Total  Debt  exceeds   sixty-five  per  centum  (65%)  of
Capitalization, then the Company shall promptly notify the Trustee and, if there
is only one Holder of  Securities of such Series,  such Holder;  and the Company
shall  redeem,  within  ninety days  thereafter  and upon at least  thirty days'
notice,  a principal  amount of the  Securities of such Series then  Outstanding
equal to a pro rata portion of the amount necessary to cause Total Debt to equal
not more.  than  sixty-five per centum (65%) of  Capitalization,  determined in
accordance with generally accepted accounting principles existing as of the date
of the First Supplemental Indenture,  such pro rata portion to be based upon the
ratio of (a) the then  Outstanding  aggregate  principal amount of Securities of
the Second Series,  to (b) the then Outstanding  aggregate  principal amounts of
Securities of the Second Series and of the Third Series; provided, however, that
to the extent the Holders of the  Securities of the Third Series waive any right
of redemption  under Section  3.03(C) of this Second  Supplemental  Indenture as
provided in such Section 3.03(C),  an additional  principal amount of Securities
of the Second Series,  in an amount equal to the amount waived by the Holders of
the  Securities  of the Third  Series,  shall be  redeemed  as  provided in this
Section 4.03(C), except to the extent waived by the Holders of the Securities of
the Second  Series.  The  Redemption  Price shall be the Second  Series  General
Redemption Price, plus interest accrued to the Redemption Date. The Holders of a
majority of the Securities of the Second Series then  Outstanding may waive such
redemption  by delivering a written  waiver to the Trustee,  in such form as the
Trustee shall deem acceptable, with a copy to the Company, within ten days after
the date of such notice of redemption.

         (D) So  long  as any  Securities  of the  Second  Series  shall  remain
Outstanding,  the  Holders of a majority of the  Securities  of such Series then
Outstanding  may,  from time to time but not more than once during any  calendar
year,  upon thirty days notice,  request that the Company file with the Trustee,
as of the end of any calendar month other than December  within sixty days after
the end of such month,  the Cash Flow  Certificate  provided in Section  4.03(A)
hereof and the Accountant's Certificates provided in Section 4.03(B) and 4.03(C)
of this Second  Supplemental  Indenture.  The same redemption  provisions  shall
apply as if such Cash Flow

                                      -15-



Certificate and Accountant's  Certificates  had been delivered  pursuant to such
Section 4.03(A), 4.03(B) or 4.03(C) of this Second Supplemental Indenture, using
with respect to Section  4.03(A) hereof the maximum for the period ending on the
December 31 next preceding such calendar month.

         (E)  Unless  otherwise  agreed  by a  majority  of the  Holders  of the
Securities of the Second Series to be Outstanding after a redemption under this
Section,  the Securities redeemed under this Section may not be used as a credit
for the  redemption  of  Securities  provided  for in Section  2.03 of the First
Supplemental Indenture.

SECTION 4.04. Restricted Payments.

         So long as any Securities of the Second Series remain Outstanding,  the
Company shall  not  declare or pay any  Restricted  Payments  unless the Company
files an  Accountant's  Certificate  with the Trustee  and, if there is only one
Holder of Securities of the Second Series,  sends a copy to such Holder,  within
thirty days prior to such  declaration or payment stating that (A) the amount of
such payment shall not exceed  cumulative  net  additions to or deductions  from
Surplus determined in accordance with generally accepted  accounting  principles
existing as of the date of the First Supplemental Indenture, made after December
31,  1992  (excluding  any  gains  on  sale of  Property  Additions  during  the
immediately  preceding 12 months in excess of twenty per centum (20%) of the net
additions to Surplus made during such 12 month period);  and (B) that after such
payment Capital plus Surplus shall equal at least  thirty-five per centum (35%)
of Capitalization,  determined in accordance with generally accepted  accounting
principles existing as of the date of the First Supplemental Indenture.

SECTION 4.05. Redemption Upon Taking of Property by Eminent Domain, etc.

           So  long  as  any  Securities  of  the  Second  Series  shall  remain
  Outstanding,  any  Officer's  Certificate  provided  under Section 1006 of the
  Original  Indenture  shall  also  state  the net book  value of the  Mortgaged
  Property described therein as taken or sold, and shall also state the net book
  value of such Mortgaged Property that does not constitute  Property Additions.
  Notwithstanding  anything to the  contrary  contained  in Section  1006 of the
  Original Indenture,  should the aggregate net book value of Mortgaged Property
  taken by the  exercise  of the  power of  eminent  domain or sold to an entity
  possessing the power of eminent  domain,  or to its designee,  under a threat,
  reasonably  believed by the Company to be genuine, to exercise the same, be in
  excess of Fifteen  Million  Dollars  ($15,000,000),  the Company shall redeem,
  within  ninety  days of such  taking  or sale and upon at least  thirty  days'
  notice, or have otherwise  retired,  except to the extent waived, an aggregate
  principal  amount of  Securities of such Series then  Outstanding  equal to an
  amount  determined  pursuant to the next sentence,  at the Redemption Price of
  par plus interest  accrued to the  Redemption  Date.  The principal  amount of
  Securities of the Second  Series to be redeemed  pursuant to this Section 4.05
  shall be calculated by dividing (1) the aggregate amount of Property Additions
  so taken or sold plus the aggregate  net book value of all Mortgaged  Property
  so taken or sold  which are not  Property  Additions  by (2) the amount of Net
  Property  Additions  shown on the most recent Property  Additions  Certificate
  filed with the Trustee and multiplying  such ratio by the aggregate  principal
  amount of Securities of such Series then Outstanding;  provided, however, that
  to the extent the  Holders of the  Securities  of the Third  Series  waive any
  right of redemption under Section 3.05 of this Second  Supplemental  Indenture
  as provided in such Section 3.05, an additional principal amount of Securities
  of the Second  Series shall be redeemed as provided in this Section 4.05 in an
  amount  equal to the amount  waived by the  Holders of the  Securities  of the
  Third Series,  except to the extent waived by the Holders of the Securities of
  the  Second  Series.  Such  redemption  shall be  prorated  among  Holders  of
  Securities  of such Series except to the extent  waived;  any Holder may waive
  its right to such redemption by delivering a written waiver to the Trustee, in
  such form as the Trustee  shall deem  acceptable,  with a copy to the Company,
  within ten days after the date of such notice of redemption; such waiver shall
  not cause a recalculation of the proration.

                                      -16-



SECTION 4.06. Maintenance of Business.

         So long as any Securities of the Second Series remain  Outstanding,  if
the Company ceases to continue  substantially in the business of providing water
and waste water utility service in the State of Florida,  then the Company shall
promptly  notify the Trustee and, if there is only one Holder of  Securities  of
such Series,  such Holder; and the Company shall redeem,  within ninety days and
upon at least  thirty days  notice,  all of the  Securities  of such Series then
Outstanding at the Second Series General Redemption Price, plus interest accrued
to the  Redemption  Date.  Any Holder may waive its right to such  redemption by
delivering a written  waiver to the Trustee,  in such form as the Trustee  shall
deem acceptable,  with a copy to the Company,  within ten days after the date of
such notice of redemption.

SECTION 4.07. Return of Redemption Moneys upon Waiver.

         Upon  receipt of any waiver of  redemption  by any Holder,  the Trustee
shall return to the Company the  redemption  money,  if any, held by the Trustee
for the redemption of such Holder's Securities.

SECTION 4.08. Special Merger Provisions.

        So long as any Securities of the Second Series remain  Outstanding,  the
Company shall not merge or  consolidate  with another  entity unless the Company
shall  have  filed  with the  Trustee,  and,  if there  is only  one  Holder  of
Securities of such Series,  such Holder, an Officer's  Certificate  stating that
(1) the Company or an entity directly or indirectly owned one hundred per centum
(100%) by  Minnesota  Power  &  Light  Company  shall  be the  continuing  and
surviving  corporation and, (2) after such merger or consolidation,  there shall
exist no Event of  Default or event  which,  with the lapse of time or giving of
notice, or both, would constitute an Event of Default, and the Company shall be
able to issue at least One Dollar ($1) of  Securities  under the  provisions  of
Section 401 or 501 of the Indenture, in each case, using a Cash Flow Certificate
stating  an  Annual  Total  Debt/Cash  Flow  Ratio not to  exceed  the  maximums
specified in Section  4.03(A) hereof (using the maximum for the period ending on
the  December  31  next  preceding  such  merger)  rather  than  the  Cash  Flow
Certificate provided in Section 301(d) of the Original Indenture.

SECTION 4.09. Bond Purchase Agreement.

        So long as  CoBank  shall be the sole  owner  of all  Securities  of the
Second Series then  Outstanding,  the Company shall redeem,  within ten days, an
aggregate principal amount of Securities of such Series, the redemption of which
is demanded,  in a certificate,  signed by the President,  any Vice President or
any Assistant Vice President of CoBank,  stating that CoBank is entitled to such
redemption under the Bond Purchase  Agreement dated March 1, 1993 between CoBank
and the Company,  describing  the event giving CoBank such right of  redemption,
and stating  that such  redemption  is  required by terms of such Bond  Purchase
Agreement.  The Redemption  Price shall be the Second Series General  Redemption
Price, plus interest accrued to the Redemption Date.

SECTION 4.10. Property Additions Certificates.

So long as any  Securities  of the Second Series shall remain  Outstanding,  the
Company shall file a Property  Additions  Certificate  with the Trustee at least
once during each calendar year.

                                      -17-



SECTION 4.11. Amendment to Indenture; Acceleration.

         So long as the aggregate  principal  amount of Securities of the Second
Series then  Outstanding,  combined,  if and only if the Holder of a majority in
aggregate  principal  amount  of  the  Securities  of  the  Second  Series  then
Outstanding  is also the Holder of a majority in aggregate  principal  amount of
the  Securities  of the  Third  Series  then  Outstanding,  with  the  aggregate
principal amount of the Securities of the Third Series then Outstanding, exceeds
twenty-five per centum (25%) of the aggregate principal amount of Securities of
all series then Outstanding, the words "twenty-five per centum (25%)" shall be
substituted for the words  "thirty-three  and one-third per centum (33 1/3%)" in
Section 1102 of the Original  Indenture.  In case any  Securities  of the Second
Series are paid by reason of a declaration of acceleration pursuant to Section 
1102 of the Original  Indenture,  the Company  shall pay to the Holders of such
Securities a premium equal to the Prepayment  Surcharge,  calculated as provided
in Section 2.02 of this Second Supplemental Indenture with respect to the Second
Series  multiplied  by the  aggregate  principal  amount of such  Securities  so
accelerated,  provided  that the  payment  of such  premium  does not render the
Company insolvent. If the aggregate principal amount of Securities of the Second
Series then  Outstanding,  combined,  if and only if the Holder of a majority in
aggregate  principal  amount  of  the  Securities  of  the  Second  Series  then
Outstanding  is also the Holder of a majority in aggregate  principal  amount of
the  Securities  of the  Third  Series  then  Outstanding,  with  the  aggregate
principal amount of the Securities of the Third Series then Outstanding, exceeds
twenty-five per centum (25%) of the aggregate  principal amount of Securities of
all series  then  Outstanding  and an Event of  Default  shall  exist,  then the
Holders of the Securities of the Second Series may demand the redemption of such
Securities of the Second Series held by them upon ten days written notice to the
Company and the  Trustee.  The  Redemption  Price  shall be the  Second  Series
General Redemption Price, respectively,  plus interest accrued to the Redemption
Date.

SECTION 4.12. Redemptions on a Business Day

         In the event any Redemption  Date for a redemption  required by Section
4.03 hereof shall not be a Business Day,  interest on the principal  amount then
due shall  accrue to and be paid on the next  Business  Day;  provided  that the
Company  may, at its option,  upon ten (10) days prior notice to the Trustee and
the Holders,  satisfy a redemption  required by Section 4.03 on the Business Day
prior to the applicable  Redemption Date at a Redemption Price equal to par plus
interest  accrued to such prior  Business  Day.  Any other  Redemption  Date for
Securities of the Second Series shall be on a Business Day.

SECTION 4.13. Amendment or Waiver of Covenants.

         The provisions of this Article Fourth may be waived or amended,  at the
request of the  Company,  with the written  consent of the Holders of at least a
majority  of the  aggregate  principal  amount of the  Securities  of the Second
Series then Outstanding. So long as the aggregate principal amount of Securities
of the Second Series then Outstanding,  combined, if and only if the Holder of a
majority in aggregate  principal  amount of the  Securities of the Second Series
then Outstanding is also the Holder of a majority in aggregate  principal amount
of the  Securities  of the Third  Series then  Outstanding,  with the  aggregate
principal amount of the Securities of the Third Series then Outstanding, exceeds
twenty-five per centum (25%) of the aggregate principal amount of Securities of
all series then  Outstanding,  the  provisions of this Article Fourth may not be
waived nor  amended  without  the  written  consent of the Holders of at least a
majority of the  aggregate  principal  amount of Securities of the Second Series
then Outstanding, except as otherwise specifically provided herein.


                                      -18-


SECTION 4.14. Covenants Superseded.

         The  provisions of this Article  Fourth shall  supersede and replace in
their   entirety  the  covenants   contained  in  Article  Third  of  the  First
Supplemental Indenture. Notwithstanding the foregoing, Sections 3.14 and 3.17 of
the First Supplemental Indenture shall remain in full force and effect.


                                  ARTICLE FIFTH

                                  Miscellaneous

SECTION 5.01. Definitions.

         Subject to the  amendments  provided  for in this  Second  Supplemental
Indenture,  the terms  defined  in the  Supplemented  Indenture  shall,  for all
purposes of this Second Supplemental  Indenture,  have the meanings specified in
the Supplemented Indenture.

SECTION 5.02. Acceptance of Trust.

         The  Trustee  hereby  accepts  the trust  herein  created and agrees to
perform the same upon the terms and  conditions  herein and in the Indenture set
forth and upon the following terms and conditions:

         The Trustee shall not be responsible in any manner whatsoever for or in
respect to the validity or sufficiency of this Second Supplemental  Indenture or
for or in respect of the  recitals  contained herein, all of which recitals are
made by the  Company  alone.  In  general  each and  every  term  and  condition
contained in Article  Sixteen of the Original  Indenture shall apply to and form
part of this Second Supplemental  Indenture with the same force and effect as if
the same were  herein  set forth in full with  such  omissions,  variations  and
insertions,  if any,  as may be  appropriate  to make  the same  conform  to the
provisions of this Second Supplemental Indenture.

SECTION 5.03. Successors and Assigns.

        Whenever in this  Second  Supplemental  Indenture  either of the parties
hereto is named or  referred  to,  this  shall,  subject  to the  provisions  of
Articles Fifteen and Sixteen of the Original Indenture, be deemed to include the
successors  and assigns of such party,  and all the covenants and  agreements in
this Second Supplemental  Indenture contained by or on behalf of the Company, or
by or on behalf of the Trustee, or either of them, shall,  subject as aforesaid,
bind and inure to the  respective  benefits  of the  respective  successors  and
assigns of such parties, whether so expressed or not.

SECTION 5.04. Benefit of the Parties.

         Nothing in this Second Supplemental Indenture, expressed or implied, is
intended, or shall be construed, to confer upon, or to give to, any person, firm
or corporation,  other than the parties hereto and the Holders of the Securities
Outstanding under the Indenture,  any right,  remedy or claim under or by reason
of this Second Supplemental Indenture or any covenant,  condition,  stipulation,
promise or agreement  hereof,  and all the covenants,  conditions,  stipulations
promises and agreements in this Second Supplemental Indenture contained by or on
behalf of the Company shall be for the sole and exclusive benefit of the parties
hereto and of the Holders of the Securities Outstanding under the Indenture.

                                      -19-


SECTION 5.05. Counterparts.

         This  Second  Supplemental  Indenture  shall  be  executed  in  several
counterparts,  each  of  which  shall  be an  original  and all of  which  shall
constitute but one and the same instrument.

         IN WITNESS  WHEREOF,  the Company  has caused this Second  Supplemental
Indenture to be executed in its  corporate  name by its  President or one of its
Vice Presidents and its corporate seal to be hereunto affixed and to be attested
by its Secretary or one of its Assistant Secretaries, and SunTrust Bank, Central
Florida,  National  Association,  to evidence its acceptance  hereof, has caused
this Second  Supplemental  Indenture to be executed in its  corporate  name by a
duly authorized  officer  thereof and its corporate seal to be hereunto  affixed
and  to  be  attested  by  a  duly  authorized   officer  thereof,  in  several
counterparts, all as of the day and year first above written.


Attest:                               FLORIDA WATER SERVICES CORPORATION,
                                      formerly known as Southern States 
Dona Henry                            Utilities, Inc.
- ----------------------------------
                                      By:  Morris Bencini
Dona Henry, Assistant Secretary          ---------------------------------------
- ----------------------------------    Name: Morris Bencini
         (Print Name)                      -------------------------------------
                                      Title: Vice President - Finance and 
                                               Treasurer
                                             -----------------------------------
                                      Address: 100 Color Place, Apopka, FL 32703
                                              ----------------------------------

In the presence of:

Kristi Jung
- ----------------------------------
             (Witness)
Kristi Jung
- ----------------------------------
            (Print Name)

Sally Murray
- ----------------------------------
             (Witness)
Sally Murray
- ----------------------------------
            (Print Name)

                                      -20-


Attest:                              SUNTRUST BANK, CENTRAL FLORIDA,
                                     NATIONAL ASSOCIATION, as Trustee 
Lisa George                           
- ----------------------------------
                                     By:  M. B. Daiger
Lisa George, Assistant Vice             ----------------------------------------
   President                         Name: M. Bruce Daiger
- ----------------------------------        --------------------------------------
         (Print Name)                Title: Vice President
                                            ------------------------------------
                                     Address:222 East Robinson Street, Suite 250
                                             -----------------------------------
                                           Orlando, FL 32801
                                     -------------------------------------------
In the presence of:

Kristi Jung
- ----------------------------------
             (Witness)
Kristi Jung
- ----------------------------------
            (Print Name)

Sally Murray
- ----------------------------------
             (Witness)
Sally Murray
- ----------------------------------
            (Print Name)


STATE OF FLORIDA         )
COUNTY OF ORANGE         )


             The foregoing  instrument  was executed  before me, an officer duly
authorized  in the state and county  aforesaid to  administer  oaths and to take
acknowledgments,  this 27 day of March 1997, by Morris Bencini as Vice President
- - Finance of FLORIDA  WATER  SERVICES  CORPORATION,  formerly  known as Southern
States Utilities,  Inc., a Florida  corporation,  on behalf of said corporation,
who is personally known to me.


[SEAL]        Lisa Freeman Schutz                      Lisa Freeman Schutz
         Notary Public, State of Florida               -------------------------
           Commission No. CC 486829                    NOTARY PUBLIC
         My Commission Expires 08/07/99

 1-800-3-NOTARY  Fla. ______ Service
     & Bonding Co.



STATE OF FLORIDA              )
COUNTY OF ORANGE              )


     The foregoing instrument was executed before me, an officer duly authorized
in  the  state  and  county   aforesaid   to   administer   oaths  and  to  take
acknowledgments,  this  27 day of  March,  1997,  by M.  Bruce  Daiger  as  Vice
President of SUNTRUST BANK, CENTRAL FLORIDA, NATIONAL ASSOCIATION,  on behalf of
said bank, who is personally known to me.


[SEAL]        Lisa Freeman Schutz                      Lisa Freeman Schutz
         Notary Public, State of Florida               -------------------------
           Commission No. CC 486829                    NOTARY PUBLIC
         My Commission Expires 08/07/99

 1-800-3-NOTARY  Fla. ______ Service
     & Bonding Co.


                                      -21-


                               BONDHOLDER CONSENT
                               ------------------


             FOR GOOD AND VALUABLE CONSIDERATION, the receipt and sufficiency of
which are hereby acknowledged, the undersigned, CoBank, ACB, f/k/a National Bank
for Cooperatives, as holder of all the Securities of the Second Series presently
Outstanding,  hereby  consents to the terms,  covenants  and  conditions of the
foregoing Second Supplemental Indenture.



                                        COBANK, ACB, f/k/a National Bank for
                                        Cooperatives

                                        By:  Thomas A. Smith
                                           ------------------------------------
                                        Name:  Thomas A. Smith
                                             ----------------------------------
                                        Title:  Senior Vice President
                                              ---------------------------------

STATE OF GEORGIA              )
COUNTY OF COBB                )

     The foregoing instrument was executed before me, an officer duly authorized
in  the  state  and  county   aforesaid   to   administer   oaths  and  to  take
acknowledgments,  this 31 day of March,  1997,  by Thomas A. Smith,  Senior Vice
President of COBANK,  ACB,  f/k/a National Bank for  Cooperatives,  on behalf of
said  corporation,  who  is  personally  known  to  me  or  who  produced 
                           as identification. 
- --------------------------


                                        Susan L. South
                                        ------------------------------------
                                        NOTARY PUBLIC

                                        Susan L. South
                                        ------------------------------------
                                        Print Name



                                      -22-