Can you connect city water to a well or other water source in Phoenix?

Section 37-142 is a single sentence: "No person may cause a connection to be made or allow a connection to exist for any purpose between the City water supply and any other source of water without the approval of the Director." Two parts matter. It reaches anyone who makes the connection and anyone who lets an existing one stay. And it applies "for any purpose," so a connection for a good reason still needs approval.

The neighboring section, 37-144, tells you what protects the city system when an auxiliary source exists. Its list names "Auxiliary water systems (air gap or RP)" and "Chemically contaminated water systems (air gap or RP)." It also lists reclaimed water and sewage and storm drain facilities (air gap or RP), interconnected multiple services (air gap, RP or double check) and industrial fluid systems interconnected with the public supply (RP or double check).

The 2024 plumbing code amendment repeats the point from the building side. Under IPC 608.7.2 as Phoenix amends it, auxiliary water systems and construction water services are among the uses that "shall have a Secondary Reduced Pressure Principle Backflow Prevention assembly installed as close as practicable to each point of service delivery." The base code text that Phoenix reproduces in that amendment also says cross connections between a private water supply and a potable public supply "shall be prohibited."

• Auxiliary water supply: any water source other than the city system. A private well is the usual example.
• Cross connection: any physical link that could let something other than city water into the city system.
• Air gap and RP: the two strongest protections. An air gap is an open space at least double the supply pipe diameter and never under an inch, and an RP is an assembly with two check valves and a relief valve.

Anyone on Phoenix city water who also has, or wants, another source: a commercial well, a nursery with irrigation wells, a cooling system with a tank, reclaimed water on site, or any system that could push water back toward the meter. Single-family homes used solely for residential purposes are exempt from the article unless a cross connection problem is specifically identified. A house that ties its well into the city plumbing has exactly that problem.

• A nursery has a well for irrigation and a city meter for the office. The two systems must not be joined. If the owner wants the city line as a backup for the well, that is a connection needing the director's approval, and an air gap or RP at the service.
• A car wash adds a reclaimed water tank. Car washes are on the backflow list already, and the reclaimed line adds an auxiliary water system, which the list also names for air gap or RP.
• A building has a cooling loop topped up from the city line. A connection already in place is covered too, because the section bars allowing one to exist.
• The same property drops the well and caps it at the meter. The answer flips: with no physical link to another source, 37-142 has nothing to approve.

1. 1List every water source on the property and how each one is piped.
2. 2Confirm nothing links a well, tank or process loop to the city side of the meter.
3. 3If a link is wanted, apply for the Water Services Director's approval before any piping is done.
4. 4Install the air gap or RP the code requires at the service, with a plumbing permit and a certified tester's first test.
5. 5Keep the yearly test records on file for three years.

• "A check valve at the well is enough." The code names an air gap or RP for auxiliary systems.
• "It is my water, so I can tie it in." The section bars a connection between city water and any other source without approval, whoever owns the source.
• "An old connection is grandfathered." The code also bars allowing a connection to exist.
• "Only businesses are covered." The section says "no person." The only carve-out is 37-144(e), which exempts single-family homes unless a cross connection problem is found.