Ariz. Admin. Code § 18-5-506
All construction shall conform to approved plans and specifications. In order to make a change in an approved design that will affect water quality, capacity, flow, sanitary features, or performance, a public water system shall submit revised plans and specifications to the Department for review, together with a written statement regarding the reasons for the change. The public water system shall not proceed with the construction affected by the design change without written approval from the Department. Revisions not affecting water quality, capacity, flow, sanitary features, or performance may be permitted during construction without further approval if record drawings documenting these changes, prepared by a professional engineer registered in Arizona, are submitted to the Department under R18-5-508.
Ariz. Admin. Code § R18-5-506