Commercial Backflow Testing in Phoenix and the Valley

A backflow test proves the assembly still does its one job: keep water from your building from running back into the city main. A certified tester hooks a calibrated differential gauge to the test cocks and checks each part against the USC Manual of Cross-Connection Control procedure Phoenix City Code 37-143 requires.

What gets measured depends on the type:

• Reduced pressure (RP) assembly: both check valves and the relief valve between them. Watts' service manual for its large RP assemblies says the relief valve must keep the zone between the checks at least 2 psi below supply pressure.
• Double check (DC) assembly: each check valve must hold tight against reverse flow, and both shutoff valves must close fully.
• Pressure vacuum breaker (PVB): the check valve and the air inlet that opens when pressure drops, usually on landscape irrigation.

Arizona's rule, A.A.C. R18-4-215, sets the clock: at least once a year, plus after any installation, relocation or repair. Your city sends the notice with the due date. The rule makes the water system send it.

Two layers decide who can sign your report. The state layer is the tester's certification. ADEQ's backflow page lists four approved certifying authorities: CA-NV Section AWWA, ABPA, ASSE (affiliated with IAPMO) and All American Backflow Prevention. The local layer is your water provider's own list. Phoenix keeps a list of approved test companies, and to get on it a company files tester certificates, repairer certificates and test kit calibrations (TRT 00638). Mesa keeps a recognized tester list under City Code 8-1-12 and drops testers whose gauge accuracy report is over a year old.

So ask two questions before you book: is the tester certified, and is the company on your city's list right now? Our page on who can test backflow assemblies in Arizona covers how to check.

Plan for a short water outage. The test closes the assembly's shutoff valves, so whatever sits behind it loses water while the gauge readings are taken. Tempe and Scottsdale both say so in code: a property that cannot have its supply interrupted for testing needs two assemblies installed side by side (Tempe 33-104(b), Scottsdale 49-63(c)). A restaurant usually books before opening. An office building books early morning.

The report is the product you're paying for. Phoenix's instructions (TRT 00335) ask for the water meter number; make, size, model and serial number; line pressure at the time of the test; initial results; any repairs, with part numbers; pass or fail; and the tester's certification number and test kit serial number. A report missing any of that is returned to the tester, and Phoenix tells the owner the certification was not accepted. Our guide to reading a backflow test report walks through the numbers line by line.

The deadline belongs to the customer even when the tester files. Mesa's code says the customer must make sure the department received the reports (8-1-11(A)). Ask for your own copy every time. Phoenix wants records kept three years, and more providers are covered in our guide on where to send backflow test reports.

Some notices can't be cleared with a test.

• The assembly fails. Then the job is a backflow assembly repair and a retest, not a second test.
• The city says you need an assembly you don't have. That's an installation with a permit. See backflow installation for new businesses.
• The assembly is on a fire line or fire sprinkler system. Phoenix requires a tester also permitted by the City Fire Marshal for those. Fire backflow assemblies and fire sprinkler work are outside what HQ does, so call your fire protection contractor.
• It's a single-family home used only as a home. Arizona's rule and Phoenix's code exempt it unless a cross-connection problem is identified.

HQ is certified to test and certify domestic backflow assemblies: RP, double check and PVB assemblies on domestic water service and irrigation. We file the results with the city, so the report lands where your notice says it should. Send us the city notice by mail or email and we'll schedule around your hours. If a test fails, the assembly has to be repaired and retested before a passing report goes in; when the right parts are on hand, both can happen on one visit, which saves a second shutoff.

You get an upfront price before any work starts, and for a site with several assemblies we put them all on one visit when the due dates allow. Related: commercial plumbing, property management plumbing, and the Valley backflow rules by city.