Exhibit 15.1 May 11, 1995 Arizona Public Service Company Post Office Box 53999 Phoenix, Arizona 85072-3999 We have made a review, in accordance with standards established by the American Institute of Certified Public Accountants, of the unaudited interim financial information of Arizona Public Service Company for the periods ended March 31, 1995 and 1994, as indicated in our report dated May 11, 1995; because we did not perform an audit, we expressed no opinion on that information. We are aware that our report referred to above, which is included in your Quarterly Report on Form 10-Q for the quarter ended March 31, 1995, is incorporated by reference in Registration Statement Nos. 33-51085, 33-57822, 33-61228 and 33-55473 on Form S-3. We are also aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1993, is not considered a part of the Registration Statement prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of the Act. DELOITTE & TOUCHE LLP DELOITTE & TOUCHE LLP Phoenix, Arizona