Backflow Testing & Prevention
Keep the irrigation backflow assembly tested and working so yard water never reaches drinking lines.
Homeowner guide
Backflow Preventer Rules and Annual Testing in Tempe, AZ
A backflow assembly keeps water that has been in sprinklers, boilers or fire lines from flowing backward into the drinking supply. In Tempe, some properties must have one and test it annually.
By the Tempe Express Plumbing team ·
What backflow is
Water normally flows from the city main into your building. If pressure drops or a pump pulls, water can run the other way and carry contamination into the supply. A backflow assembly stops it.
The city has a program to protect the public water supply and tracks tests, investigates complaints and enforces the rules.
Who needs an assembly
According to the City of Tempe, single-family homes used only as homes are exempt under state rules. Other residences, plus commercial and industrial customers, must install and maintain assemblies under Tempe City Code Chapter 33 and an Arizona rule, R18-4-215.
An Environmental Compliance Inspector decides case by case and notifies the bill payer in writing. Fire lines should be protected by a double check assembly.
Annual testing
The assembly must be tested when installed and then each year by a certified tester, paid for by the customer. The city sends a notice on the utility bill before the test is due.
After any repair or maintenance, the assembly is retested and the results are submitted to the city. Keep test and repair records for at least three years.
Backflow testing at a glance
Key points from the City of Tempe.
| Topic | What the city says |
|---|---|
| Who needs one | Non-exempt residences, commercial and industrial customers |
| Testing | Annually by a certified tester |
| After repairs | Retest right away and submit results |
| Permits | Needed to install or replace an assembly |
Choosing a tester
Tempe provides a list of certified testers. Prices vary, so get several quotes. A tester should be certified, and the report is filed with the city.
Ask whether the same company can repair a failed assembly, and what a retest costs.
Installing or replacing an assembly
Installation or replacement needs a permit from the Building Health note Division. The assembly belongs as close as possible to the service connection on private property.
Variances are available through the Backflow Prevention Section of the city.
Missing a notice
If a test is not completed, the city issues an overdue notice. It may take enforcement action, up to ending water service, if compliance does not follow.
Do not wait for the last day. Book a tester as soon as the notice arrives.
Hose bibs and home irrigation
Even exempt homes benefit from simple protection. Hose bib vacuum breakers keep garden hoses from pulling dirty water back into the house. They are cheap and easy to replace.
The faucet and sink repair page covers hose bibs.
Who to call
The city's Environmental Services Section handles compliance questions and extensions. For testing and repair, backflow testing and prevention explains what a contractor does.
Property managers with several assemblies should keep a calendar of due dates.
What the assembly looks like
A backflow assembly is a set of valves in a short length of pipe, usually installed above ground near the meter or on the irrigation line. It has test cocks, small fittings with caps that the tester uses to check the valves. Some types have a vent that may spit water when pressure changes, which is normal for that design.
Knowing what you have helps when you call a tester. Note the brand, the size and any tag on the device, and take a photo. Include the address and the account number from the utility notice.
Caring for the assembly through the year
Keep the area around the device clear of plants and debris. Water pooling around it, a constant drip from the vent or visible cracks in the body are signs it needs service. In a freeze, insulate the assembly, though freezing is a rare concern in the Valley compared with the heat that bakes plastic parts.
If the assembly is in a box, check that the lid is intact and the box drains. A flooded box can hide leaks and corrode fittings.
Records to keep
Hold on to each test report and the repair invoice. The City of Tempe asks that results be submitted after testing, and a copy in your files proves the work was done. If the property is sold, the new owner will need the history.
Ask the tester how and when results reach the city, and whether they file on your behalf. The backflow testing page explains what a typical visit covers and how repairs and retests are handled.
Common questions owners ask testers
Owners often ask whether a failed test means the whole assembly must be replaced. Not always. Many failures come from a fouled check valve or a worn rubber seat, and the tester can swap internal parts, then retest the same day. A full replacement is more likely when the body is cracked or the model is obsolete.
Another frequent question is whether the irrigation system can keep running while the assembly is down. Most testers need the water off for a short window, so plan around the sprinkler schedule. Ask when the system will be back in service and whether the tester will leave the valves in the correct position.
Landscaping contractors sometimes move or bury an assembly during a project. If that happened, the device may no longer meet the height and clearance rules. Tell the tester about any recent work so they can note it on the report.
Finally, ask what the tester charges for the retest after a repair. Practices differ, and the answer should be in the quote before the visit begins.
Planning a landscaping project
Before a new irrigation zone, a pool autofill or a fountain goes in, ask the installer whether the work touches the backflow assembly. Moving a device, adding a branch ahead of it or burying it can break the rules and trigger a failed test. A short call to the city before the work starts costs far less than redoing it.
Ask the landscaper to leave the assembly accessible, with room to reach the test cocks and the shutoff valves. Include that requirement in writing so it survives a change of crew.
Short answers
Backflow preventer questions
Single-family homes used only as homes are exempt under state rules. Other properties may need one, and the city decides.
Every year, by a certified tester, according to the City of Tempe.
It is repaired and retested right away, and the results go to the city.
Tempe provides a list of certified testers. Compare quotes.
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Faucet & Sink Repair
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Water at the handle, the spout or the wall behind a hose bib each mean something different. See which one you have.
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Reasons for a high water bill
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Sources
Figures and statements on this page that come from outside references are listed here.
Backflow test notice in the mail?
Call the 24/7 line and mention the notice. A dispatcher lines up a local contractor.