EXHIBIT 5


                                February 12, 1998


Arizona Public Service Company
400 N. Fifth Street
Phoenix, AZ 85004

Ladies and Gentlemen:

         You have  requested our opinion as counsel for Arizona  Public  Service
Company,  an  Arizona  corporation  (the  "Company"),  in  connection  with  the
registration  under the  Securities  Act of 1933, as amended,  and the rules and
regulations  promulgated  thereunder,   and  the  proposed  offering  of  up  to
$4,000,000 of deferred compensation  obligations under the Pinnacle West Capital
Corporation,  Arizona Public Service Company,  SunCor Development Company and El
Dorado  Investment   Company  Deferred   Compensation  Plan  (the  "Plan"),   as
contemplated  in the  Registration  Statement  on Form S-8 to be filed  with the
Securities  and  Exchange   Commission  on  or  about  February  12,  1998  (the
"Registration Statement").

         We have examined the Company's  Registration  Statement,  the Plan, the
Articles of Incorporation and By-Laws of the Company, and resolutions adopted by
the Company's Board of Directors.  In addition,  we have examined such corporate
records,  certificates,  and other  documents (of which we are aware) as we have
considered necessary or appropriate for the purposes of this opinion.

         On the basis of the foregoing,  it is our opinion that the  obligations
under the Plan will,  when arising under the Plan in accordance  with its terms,
constitute valid and binding obligations of the Company.

         In connection  with this opinion,  we have assumed the  authenticity of
original  documents and the  genuineness of all signatures and the conformity to
the originals of all documents submitted to us as copies.

         Our opinion is qualified to the extent that  enforcement of obligations
issued under the Plan may be subject to applicable  federal or state bankruptcy,
insolvency,  reorganization,  arrangement, moratorium, fraudulent conveyance, or
other laws or court  decisions  relating to or affecting the rights of creditors
generally and may be limited by equitable  principles of general  applicability,
including without limitation concepts of materiality, reasonableness, good faith
and fair dealing,  equitable  subordination,  and the possible unavailability of
specific performance or injunctive relief (regardless of whether considered in a
proceeding in equity or at law or whether codified by statutes).

Arizona Public Service Company
Page 2
February 12, 1998


         We  consent  to  the  filing  of  this  opinion  as an  exhibit  to the
Registration Statement.

                                            Very truly yours,


                                            /s/ Snell & Wilmer L.L.P.