Restaurant Backflow Testing in the Phoenix Valley

Most Valley restaurants carry backflow protection in two places, and both can come due.

At the water service. Cities treat a restaurant as a building that could push contaminated water back into the main. Phoenix City Code 37-144 lists "supermarkets, butcher shops, and restaurants" for an air gap or a reduced pressure (RP) assembly. Mesa's list in City Code 8-1-8 says restaurants and convenience stores need an RP. Scottsdale's list in Revised Code 49-62 says the same. That assembly usually sits outside, near the meter, often shared with other tenants in a strip center.

At the equipment. Inside, the plumbing code and the county health rules protect your own water from your own machines. The soda carbonator is the big one. Maricopa County's food establishment construction guide wants an RP or another testable device on the carbonator supply. Mesa goes further and names a device for each machine in City Code 8-1-9.

A restaurant can have an RP at the meter, another on the soda line and a smaller device on each ice maker. The city's notice usually covers the service assembly. The point-of-use RP is your job to track, though Mesa expects its reports too.

The carbonator pushes carbon dioxide into water under pressure. If a check valve leaks, that gas can flow back into the building's water line. A Public Health Reports study, kept in the CDC's library, tied illness at drink machines to exactly this: cases "seemed to occur only after a faulty check valve allowed carbon dioxide to flow into a copper waterline." Carbonated water dissolves copper, and the next drinks carry it.

So the county rule has two halves. Put a testable RP between the water line and the carbonator. Then keep copper and brass out of the run after it, using flexible line or stainless instead. Mesa's code says the same about copper downstream of a point-of-use assembly where water is carbonated or treated by reverse osmosis. A beverage vendor who swaps carbonators and reuses old copper tubing has undone the protection. For the full machine-by-machine breakdown, see soda and ice machine backflow rules.

A test shuts water off behind the assembly while the gauge readings are taken, so timing matters.

• The service assembly cuts water to the whole restaurant during the test. Book it before prep starts or after close.
• The carbonator RP only takes the soda system down. Test it during a slow stretch, and tell the bar.
• Group the visits. Testing the service assembly and the point-of-use RP on the same visit means one outage and one report packet.

Mesa adds two rules that matter to a busy kitchen. Point-of-use assemblies have to sit no more than 5 feet above the floor and be reachable, even if a panel has to come off. And a point-of-use RP needs an air-gapped drain line at least as large as the assembly, run to a floor sink or mop sink, never a flexible hose. An RP that dumps water behind the soda rack is a slip hazard, and it often means a part needs attention. See why an RPZ spits water.

Some soda systems only have a small ASSE 1022 dual check. The county accepts it as the minimum, but it has no test cocks, so no tester can certify it. Its rule instead is a written maintenance policy with an annual inspection. If you'd rather have a yearly test report to hand an inspector, the county calls a testable RP "highly recommended," and swapping one in is an installation, not a test.

Likewise, if your restaurant is new to a space that wasn't a restaurant before, the city may require an assembly that isn't there yet. That's a permit job. See backflow installation for a new business and what a change of use triggers.

HQ is certified to test and certify domestic backflow assemblies, and we file the results with the city. For a restaurant that means the service assembly, the carbonator RP and the double checks on ice makers. We work on the water side of the machine, not the machine itself. If a test fails, we can usually rebuild the assembly the same visit and retest it, covered on our backflow assembly repair page.

Send us the city notice and your opening hours, and we'll schedule the test around them. You get an upfront price before work starts, and 24/7 emergency service when something can't wait. Related: restaurant plumbing, bars and breweries, commercial backflow testing and hydro jetting for the drain side of the kitchen.