Who is allowed to test backflow assemblies in Arizona?

Arizona's backflow rule is A.A.C. R18-4-215. It says the tester must be "currently certified as a 'general' tester." The certificate has to come from a body the Arizona Department of Environmental Quality (ADEQ) approves. The rule text names two: the California-Nevada Section of the American Water Works Association, and the Arizona State Environmental Technical Training (ASETT) Center. It then adds "or other certifying authority approved by the Department."

ADEQ's own backflow page (last updated August 2026) lists the organizations it currently approves:

ASETT isn't on ADEQ's current list, even though the rule text still names it. Got a tester whose only certificate comes from a body that isn't listed? Ask your water provider if it will take their reports. Do that before you book.

The test method is set by the state too. R18-4-215 says testing follows "Section 9 of the Manual of Cross-Connection Control," the USC Foundation's manual. Phoenix City Code 37-143 requires the same manual.

Your water provider decides whose reports it accepts. Here's what the bigger Valley programs ask of a tester before they'll take a report:

• Phoenix: To get on the city's list of backflow test companies, a company submits a tester application for each tester, a tester certificate, a repairer certificate, test kit calibrations, a Phoenix privilege (sales tax) license and an Arizona Registrar of Contractors license. The ROC license isn't needed for a company that "will only be testing" and won't do work that needs a permit. The city publishes an Approved Backflow Tester Company List, dated August 11, 2026 as of this writing.
• Mesa: Only a "recognized backflow prevention assembly tester" may test or maintain assemblies in the city (City Code 8-1-12). Getting recognized takes an application, a signed City of Mesa Backflow Assembly Tester Agreement, proof of certification and a current gauge calibration report. Calibration has to be redone every year.
• Scottsdale: Installation, testing, repair and replacement "shall only be performed by an individual certified and approved by an agency recognized by the Division," and the city can suspend a tester for improper work or reporting (Revised Code 49-65).
• Glendale: Testers retest for certification every three years, submit gauge calibrations yearly, and face a written warning, then 3-month and 6-month suspensions from the recognized list for bad or incomplete reports.
• Chandler: The city lists testing companies it has verified as holding an active Registrar of Contractors license and insurance.
• Surprise: Testers need a valid Arizona backflow tester certification from an ADEQ-recognized organization, a business license, liability insurance and two calibrated test gauges.

Fire lines are a special case. In Phoenix, the initial and annual test on a fire system has to be done by a certified tester "who is also permitted by the City Fire Marshal to test fire lines or fire sprinkler systems" (City Code 37-143). Mesa keeps a separate list of recognized fire contractors for the same reason. For a fire system, hire a fire protection contractor on your city's fire list.

### More Valley programs, same idea

The list rule isn't just a big-city thing. Tempe's code says testing and repairs must be done by "a certified backflow prevention assembly tester that is approved by the department" (City Code 33-107). Peoria requires a "City of Peoria Recognized Tester" and updates its approved list monthly. Gilbert's Backflow Prevention Department keeps a list of recognized testers and provides it on request. Goodyear requires a certified general tester under the state rule, and testers working in Goodyear "must register with the Environmental Programs Division" (City Code 14-11-3).

Local test steps can differ, too. Glendale makes testers run an extra backpressure check on every pressure vacuum breaker and mark it pass or fail. A tester who doesn't know that step turns in a report Glendale can reject. That's one more reason to hire someone who already works in your city.

### Two quick scenarios

A landscaper offers to swap your irrigation PVB. In Scottsdale, installation and replacement are limited to certified, approved individuals, not just testing (Revised Code 49-65). A landscaper without that credential can't do the swap, and the new assembly still needs a passing test.

Your tester's certificate expired last month. Glendale says that if a tester's certificate isn't current, "the test reports will not be accepted." Mesa removes testers who let certification lapse from its recognized list. Either way, you'd pay for a test that doesn't count.

### How cities police their own lists

Being on a list isn't permanent. Phoenix tracks report quality and disciplines testers for it. After at least ten verified incomplete or inaccurate reports in a year, a tester gets a written warning by certified mail. Ten more within the next year means a three-month suspension from the recognized list, and continued problems bring a six-month suspension. Phoenix can remove a tester permanently for "submitting false test results," and a suspended tester has to file a new application to come back (TRT 00641). That's good news for owners: a tester in good standing on the current list has a track record the city is watching.

Testing and repairing aren't the same credential. Phoenix City Code 37-143 says repairs must be done "by a certified repairer" following ASSE Standard 5130, which is why Phoenix asks test companies for a repairer certificate on top of the tester certificate.

Five minutes of checking saves a rejected report:

1. 1Ask for the certificate number and expiration date. Phoenix's test report form requires the tester's certification number and test kit serial number, so a legitimate tester has both ready.
2. 2Find them on your provider's list. Phoenix, Chandler, Scottsdale and Glendale all publish lists. EPCOR and Arizona Water Company post certified tester lists too.
3. 3Ask when their gauge was last calibrated. Mesa and Glendale treat a calibration older than a year as a problem.
4. 4For a fire line, confirm the fire permit. In Phoenix that's a City Fire Marshal permit in addition to the tester certification.
5. 5Confirm they'll file the report. Ask where and when they'll send it, and get your own copy.

For where each provider takes those reports, see where to send backflow test reports in the Phoenix area. For the annual test itself, read commercial backflow testing requirements in Arizona, and for the rule text, see Arizona's R18-4-215 backflow rule.

HQ Plumbing & Air tests and repairs backflow assemblies on domestic water and irrigation lines. Free estimates, upfront pricing.