What Is Backflow Testing and Do I Need It?

Backflow testing is a yearly check that proves the device protecting your drinking water from dirty water flowing backward is still working. You need it if your home or business has a testable backflow assembly, which is common on businesses, irrigation systems, fire sprinklers and some pools, and your water provider will usually send a notice when it is due.

Our family has run Phoenix Plumbing Co. since 2012, and we get a lot of calls from folks holding one of those notices and wondering what it means. Here is the plain-English version.

What Backflow Is and Why It Matters

Water is supposed to flow one way: from the city main into your pipes. Backflow is when it reverses. It can happen two ways:

• Back-siphonage. Pressure in the city main drops, say from a water main break or firefighters pulling hard on a hydrant, and water gets sucked backward out of your pipes.
• Back-pressure. Something on your side, like a pump or a boiler, pushes water back toward the main at higher pressure.

Either way, whatever is sitting in your lines can get pulled into the public water. On an irrigation system, that means lawn fertilizer and weed killer. At a restaurant or a medical office, it can be much worse. A backflow preventer is a one-way valve assembly that stops that from happening.

Who Needs Backflow Testing in Phoenix

Not every house has a testable device. Here is who usually does:

• Businesses, especially restaurants, salons, dental and medical offices, car washes and anything with chemicals.
• Homes and HOAs with an irrigation system tied to the drinking water line.
• Buildings with fire sprinkler systems.
• Some homes with pool auto-fill lines, water treatment equipment or a separate landscape meter.

If your property has one, cities around the Valley generally require it to be tested at least once a year, with the results filed with the water provider. If you get a letter, do not set it aside. Missing the deadline can lead to follow-up notices and, in some cases, service interruption.

What Happens During Backflow Testing

The test usually takes well under an hour. The plumber attaches a test kit to small ports on the assembly, briefly shuts off water, and checks that each check valve holds and the relief valve opens when it should. If everything passes, the paperwork gets filed. If a part fails, it is usually a worn rubber seal or a spring, and the assembly gets rebuilt and retested.

Our backflow prevention and testing service covers the test, repairs and paperwork, and you see the flat-rate price before we lift a wrench.

A Real Story from a Phoenix Business

A small cafe owner off Indian School called us after getting a second notice from the city. Her old plumber had retired, and nobody had tested the assembly in two years. When we tested it, the relief valve was stuck from hard-water scale and would not open.

We rebuilt the assembly, retested it, and filed the results the same day. She told us she had no idea the device existed until the letters came. That is common. For business owners, our commercial plumber in Phoenix team keeps a reminder so the yearly test never sneaks up again.

What Backflow Testing Will Not Tell You

A passing test means the assembly works. It does not mean the rest of your plumbing is healthy. It will not find a slab leak, a failing water heater or a corroded supply line. And many homes do not have a testable device at all. For them, a simple vacuum breaker on hose bibs does the job, and there is nothing to test.

If you want a full picture of your system, our plumbing inspections and maintenance visit includes a 40-point inspection. Read more about timing in how often you should get a plumbing inspection.

Schedule Backflow Testing With Phoenix Plumbing Co.

If you got a notice or you are not sure whether your property needs backflow testing, call Phoenix Plumbing Co. and talk to our live Phoenix dispatcher. We are a three-generation, family-owned company with upfront flat-rate pricing and a written workmanship warranty. Call 602-834-1208.