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Backflow preventer testing: the rules, the test and how to sell it every year
Backflow testing is one of the few plumbing services that comes back every year by rule. Here is what gets tested and what can't be, who is allowed to test, how often, the test at a high level, how results reach the water purveyor, and how to quote it as a recurring business.
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Most plumbing work is one and done. Backflow testing isn't. Where a water utility requires an assembly to be tested, it has to be tested again next year, and the year after, and the report has to land on the utility's desk each time. For a certified tester, that's a customer list that renews itself.
This guide covers what a backflow test checks, which devices can be tested, who can test them, how often, how the test runs, where the report goes, and how to price it. The rules come from the EPA's Cross-Connection Control Manual, two state rules (Texas and California) and a manufacturer's manual.
Backflow rules are set by states, local health agencies and water utilities, and they differ. Treat Texas and California below as examples, not your rules. Before you test or quote, check your state's rule and your water purveyor's requirements. This is general information, not legal advice.
What backflow testing is
A backflow prevention assembly keeps water from a customer's system, such as irrigation, a boiler or a car wash, from flowing back into the public supply. A field test confirms the parts inside still do their job. On a reduced pressure principle assembly, the EPA manual describes a test with a differential pressure gauge that checks three things: the first check valve is tight and holds at least 5 psi differential, the second check is tight against backpressure, and the relief valve opens at least 2 psi below inlet pressure.
The test is done under no-flow conditions, which is why the water to the building goes off while you test.
Testable assemblies vs devices you can't test
What makes an assembly testable is test cocks and shutoff valves built into it. ASSE International publishes the product standards most of these are certified to.
| Device | ASSE standard | Field testable? | Notes |
|---|---|---|---|
| Reduced pressure principle (RP, RPZ) | 1013 | Yes | Relief valve between two checks; used on high hazards |
| Double check valve assembly (DC, DCVA) | 1015 | Yes | Two checks, test cocks and two shutoff valves |
| Pressure vacuum breaker (PVB) | 1020 | Yes | Backsiphonage only; test cocks added to an atmospheric breaker design |
| Spill-resistant vacuum breaker (SVB) | 1056 | Yes | Backsiphonage only |
| Atmospheric vacuum breaker (AVB) | No | The EPA manual says AVBs can't be tested once installed | |
| Residential dual check | 1024 | No | Installed at the meter; made without test cocks or gate valves |
The four testable types are the same four on the ASSE 5110 tester practical exam (ASSE 1013, 1015, 1020 and 1056 assemblies), and California's Cross-Connection Control Policy Handbook lists field test procedures for the RP, DC, PVB and SVB, plus their detector versions (RPDA, DCDA).
Who may test
Almost everywhere, a plumbing license alone isn't enough. The state or the utility wants a certified or licensed tester.
ASSE 5110 certification
ASSE 5110 is the professional qualification standard for backflow prevention assembly testers. ASSE lists the requirements as at least five years of documented experience in plumbing, mechanical, fire protection, lawn irrigation or a related field; a training course of at least 40 hours; a 100-question exam passed at 70% or higher; and a practical exam. Certification lasts three years.
Texas
Texas rule 30 TAC §290.44(h)(4) requires a licensed backflow prevention assembly tester. Testers must complete a course approved by the TCEQ's executive director, pass the state exam and hold a current license. They may test and repair assemblies on domestic, commercial, industrial and irrigation services, but on fire lines only if they are permanently employed by an Approved Fireline Contractor.
California
California's Cross-Connection Control Policy Handbook requires required field tests to be done by a tester certified by an organization the State Water Board recognizes. ASSE says the Board recognized its 5110 program in a letter dated June 17, 2025, and that this recognition runs until July 1, 2027. The Handbook says that starting three years after its effective date of July 1, 2024, only certifications from organizations accredited to ISO/IEC 17024 by ANAB (or a body with a mutual recognition arrangement with ANAB) will count. If you test in California, check that your certifier is on the Board's list for 2027.
Other states run their own programs. Before you buy a test kit, find out which certification your state and your local utilities accept.
How often
- Texas: every required assembly is tested on installation. Assemblies that protect against health hazards must also be tested at least annually.
- California: assemblies are field tested at least annually, and after installation, repair, depressurization for winterizing, or permanent relocation. The water system may require more frequent tests for high hazards. An assembly that fails must be repaired or replaced within 30 days of notice of the failure, unless the system's plan allows an extension.
- The manufacturer: Watts's manual for its Series 009 reduced pressure zone assemblies says the product must be tested periodically per local codes, but at least once per year.
Annual testing is the common pattern, but the anniversary date, the deadline and the grace period come from the utility's letter. Read it.
The test, at a high level
The EPA manual lists the steps before any test. Your state may require a specific procedure; California's Handbook names the USC Foundation for Cross-Connection Control and Hydraulic Research's Manual of Cross-Connection Control, Tenth Edition, or an equivalent.
- Get permission to shut the water off. Hospitals and process plants can't lose water without a planned shutdown. Tell the owner nobody should use water during the test, since unprotected cross-connections inside could siphon back while the pressure is down.
- Identify the assembly and find the flow direction from the arrow on the body.
- Number the test cocks, bleed them of debris, and fit the adapters you need.
- Close the number 2 shutoff valve.
- On an RP, wait a few moments before hooking up. If water keeps coming out of the relief valve, the first check is probably fouled and there's no point testing until it's serviced.
- Connect the test kit hoses as the procedure for that assembly and that step requires, then run the test and record each reading.
Keep your gauge calibrated. Texas requires test gauges to be checked for accuracy every year, and testers must put the gauge serial number on the state's report form.
Reporting the result
The test isn't done until the water purveyor has the report. In Texas, the tester completes a report for each assembly on the Backflow Prevention Assembly Test and Maintenance Report (TCEQ Form 20700, or an approved equivalent), and the signed and dated original goes to the public water supplier. In California, the water system must require testers to notify it as soon as possible within 24 hours if they see a backflow incident or an unprotected cross-connection during a test.
Each utility sets how it wants reports (paper, email or an online system) and by when. Ask every utility you work with, and keep your own copy with the customer's file.
Pricing backflow testing as a recurring business
Price it like a route, not a service call. Your costs are the drive, the time on site, the paperwork and the follow-up, and the job repeats every year.
What to put on the quote
- Test fee per assembly, with a lower price for each additional assembly at the same address
- Report filing with the utility, plus any filing fee the utility charges
- Trip charge outside your normal route; see our guide to the plumbing service call fee
- Repair, priced separately: rubber parts kit, check or relief valve parts, labor, and a retest after the repair
- Replacement if the assembly can't be repaired or parts aren't available
- Enclosure, insulation or winterizing where the assembly sits outdoors in freezing weather
An example
The numbers below are an example only, not market prices. Use your own costs from your plumbing price book.
| Line | Example price |
|---|---|
| Annual test, first assembly (irrigation RP) | $95 |
| Annual test, second assembly, same address (domestic DC) | $60 |
| Report filing with the water utility | $15 |
| Total if both pass | $170 |
| If the RP fails: rubber kit, labor and retest | $240 |
Quote the repair before you start it, and get it signed. The customer just learned their test failed and has a deadline from the utility; a written price keeps that conversation simple.
The reminder list
The real asset is the list. For each assembly, keep the address, the type, make, model, size and serial number, the location on site, the utility and its due date, last year's readings and any repairs. Then:
- Contact customers 30 to 60 days before their due date, and book them by neighborhood.
- Bring the right kit. Last year's notes tell you the model, so the repair kit can be on the truck.
- Offer a multi-year price to property managers with many assemblies.
- Treat every test as a look around. A failing RP, a leaking relief valve or a missing hose bibb vacuum breaker are all quotes. For more ways to grow repeat work, see our plumbing marketing ideas.
Plumbo, now on the App Store and Google Play, turns a voice note like "RP failed, needs a rubber kit and a retest" into a quote from your own price book. The customer signs on your phone, and the approved quote becomes the invoice in one tap. Try the 60-second demo →
Sources
- U.S. Environmental Protection Agency, Cross-Connection Control Manual (PDF, EPA 816-R-03-002, 2003: device types, AVB and residential dual check, pre-test steps, RP field test), checked October 10, 2026.
- Texas Administrative Code, 30 TAC §290.44, Water Distribution (via Cornell LII: subsection (h)(4), testing frequency, tester license, fire lines, gauges, Form 20700), checked October 10, 2026.
- California State Water Resources Control Board, Cross-Connection Control Policy Handbook (PDF, effective July 1, 2024, amended April 21, 2026: §3.3.3 testing and repair, §3.4.1 tester certification), checked October 10, 2026.
- ASSE International, Backflow Prevention certifications (ASSE 5110 requirements), checked October 10, 2026.
- ASSE International, ASSE 5110 Backflow Prevention Assembly Tester Certification in California, checked October 10, 2026.
- ASSE International, Product Standards (ASSE 1013, 1015, 1020, 1024, 1056), checked October 10, 2026.
- Watts, RP/IS-009 Installation, Maintenance, and Repair Manual, Series 009 Reduced Pressure Zone Assemblies (PDF: testing at least once per year, repair kits), checked October 10, 2026.