July 2, 1998



Arizona Public Service Company
400 North Fifth Street
Phoenix, Arizona  85004

Ladies and Gentlemen:

         Reference is made to (a) your proposed  offering of up to  $400,000,000
of  your  Securities  (the  "Securities"),   as  contemplated  by  the  combined
prospectus   contained  in  the   Registration   Statement  (the   "Registration
Statement") on Form S-3 to be filed by you on July 2, 1998,  with the Securities
and  Exchange  Commission  under the  Securities  Act of 1933,  as amended  (the
"Act"), which Securities include (i) $350,000,000 of New Bonds, Senior Notes, or
Debt Securities (as such terms are defined in the  Registration  Statement),  or
any  combination   thereof,  to  be  registered  pursuant  to  the  Registration
Statement,  (ii) $50,000,000 of New Bonds, Senior Notes, or Debt Securities,  or
any combination thereof, previously registered under Registration No. 333-27551;
and (b) any registration statement registering additional Securities pursuant to
Rule 462(b) of the Act that  relates to the  Registration  Statement  (the "Rule
462(b) Registration Statement").

         We have examined originals or copies, certified or otherwise identified
to  our  satisfaction,   of  such  corporate  records,   agreements,  and  other
instruments,   certificates,   orders,  opinions,   correspondence  with  public
officials, certificates provided by your officers and representatives, and other
documents as we have deemed necessary or advisable for the purposes of rendering
the opinions set forth herein.

         Based  on  the  foregoing,  it  is  our  opinion  that  after  (i)  the
Registration   Statement,   and  the  Rule  462(b)  Registration  Statement,  if
applicable,  shall have become effective, (ii) all required regulatory approvals
have  been  obtained,  and  (iii)  you  shall  have  entered  into  one or  more
underwriting or  distribution  agreements with respect to the Securities then to
be offered and the initial public offering price for each of such Securities and
the discounts  therefrom and commission  therefor shall have been  determined in
accordance with such  underwriting or distribution  agreements,  pursuant to the
authorization of your Board of Directors and the applicable order of the Arizona
Corporation  Commission,  then, when (i) the Securities have been issued,  sold,
executed, authenticated, and delivered, and (ii) the purchase price therefor has
been paid to you as  contemplated  in the  Registration  Statement  and the Rule
462(b) Registration Statement, if applicable

Arizona Public Service Company
July 2, 1998
Page 2



(including the Exhibits  thereto),  and in any relevant  amendment thereto or in
any  Rule  424  supplement  to the  prospectus  contained  in  the  Registration
Statement,  the  Securities  will be validly issued and will  constitute  legal,
valid,  and binding  obligations of you except as the same may be limited by (a)
general  principles  of equity  or by  bankruptcy,  insolvency,  reorganization,
arrangement,  moratorium,  or other laws or equitable  principles relating to or
affecting  the  enforcement  of  creditors'  rights  generally,  or by equitable
principles  that limit the right to  specific  performance  or  otherwise  limit
remedial action or the enforcement of the security  provided for the Securities,
(b) the necessity for  compliance  with the  statutory  procedural  requirements
governing  the  exercise  of  remedies  by  a  secured  creditor,  and  (c)  the
qualification that certain waivers,  procedures,  remedies, and other provisions
of the Securities may be unenforceable  under or limited by the law of the State
of Arizona;  however, such law does not in our opinion substantially prevent the
practical  realization of the benefits thereof.  In giving the above opinion, we
have assumed that the law of the jurisdiction or  jurisdictions  that govern the
Securities is substantially the same as the law of the State of Arizona.

         Consent  is  hereby  given  to the use of this  opinion  as part of the
Registration   Statement,   and  the  Rule  462(b)  Registration  Statement,  if
applicable,  and to the use of our name wherever it appears in said Registration
Statement,  the related prospectus,  and the Rule 462(b) Registration Statement,
if applicable.

                                           Very truly yours,


                                           Snell & Wilmer L.L.P.
                                           Snell & Wilmer L.L.P.