Most do. Arizona's Valley cities require a backflow assembly on master-metered apartment complexes, tall buildings, buildings with booster pumps or tanks, and landscape irrigation, and every required assembly needs annual testing by a certified tester. A typical complex has several: the main service, irrigation, pools and fire sprinklers.
When an apartment or condo property needs an assembly
Each city writes its own list, but the lists point the same way. Here's what four Valley codes say about multifamily properties.
| City | What triggers a backflow assembly | Device |
|---|---|---|
| Mesa | "Mobile home parks, RV parks, master planned communities, commercial plazas, apartment complexes, or any other property that is served by one or more master meters" | RP (City Code 8-1-8) |
| Scottsdale | "Master metered apartments, condos and townhouses with more than two units per meter" | RP (Revised Code 49-62) |
| Phoenix | "Multi-storied buildings having booster pumps or above ground storage tanks"; mobile home parks and RV parks | Air gap, RP or DC; RP or DC for parks (TRT 00635) |
| Tempe | Buildings greater than 3 stories or 34 feet in height; buildings with booster pumps or potable water storage; mobile home parks | Type set by the city's table (City Code Chapter 33) |
Height and pumps matter in the other cities too. Scottsdale requires an RP on buildings with plumbing "greater than thirty-four (34) feet in height" from the service connection, and on buildings with "house pumps and/or potable water storage tank." Mesa's list also covers buildings over three stories or 34 feet.
Look closely at Scottsdale's wording: more than two units per meter. A townhome row where every unit has its own meter may not trip that rule. A garden-style complex on one master meter almost always does.
Why most complexes have several assemblies
The meter-side assembly is only the start. A multifamily property usually has water uses that each need their own protection.
- Landscape irrigation. Phoenix requires a PVB on an irrigation system not subject to backpressure, and an RP where the system uses chemical injection, has areas higher than 6 inches below the PVB, or has multiple services (TRT 00635). Mesa requires a PVB on irrigation served by a dedicated landscape meter. A "dual use" meter that serves both domestic and landscape needs must have its landscape connection isolated with an RP or PVB (City Code 8-1-8).
- Pools and spas. Mesa lists "Public or semi-private swimming pools with self-levelers or automatic fillers," with a PVB at the point of use or an RP at the service connection. Its point-of-use list also covers swimming pool fill lines.
- Fire sprinklers. Phoenix says that "essentially, all potable water supplies to fire lines serving fire protection systems require installation of backflow" protection (TRT 00635). That's a separate assembly on the fire service.
- Clubhouse and amenity equipment. A fitness center, a clubhouse kitchen or a car wash bay can each add point-of-use devices under a city list like Mesa's. A car wash bay also needs a sand and oil interceptor on its drains; see car wash sand and oil interceptors in Arizona.
On a big property, that can mean one assembly at each meter, one for each irrigation service or landscape meter, one per pool and one on each fire service. Each one has its own serial number, its own test date and its own report.
The yearly test
Arizona's backflow rule, A.A.C. R18-4-215, requires a required assembly to be tested at least once a year by a certified tester. Phoenix puts it this way: "The customer shall test all backflow prevention assemblies at least once a year," and the city can require more often if warranted (TRT 00635). The customer must also submit the results. If a test shows a defect, the customer has to repair or replace the assembly until it's in satisfactory condition.
Fire sprinkler assemblies follow stricter rules. In Phoenix, the initial and annual test on a fire line assembly "shall include a full flow test," and the tester must be permitted by the city Fire Marshal to test fire lines or fire sprinkler systems. Results go to both the Director and the Fire Marshal within 30 days of the inspection. That test is fire system work, so it goes to a fire-licensed contractor.
### Who is responsible at an apartment property
The duty sits with the "customer," which Phoenix City Code 37-143 defines as "any person that has physical control, authority or responsibility for a water system." At a complex, that's usually the owner, the HOA or the management company, not the tenants in individual units. What that means in practice:
- The owner or manager books the tests. It's simplest to have one certified tester handle every domestic and irrigation assembly on the property.
- The reports go in under each serial number. Keep a list that maps each assembly to its location, so a missed one doesn't slip through.
- Deadlines don't move for turnover. When a property is sold or a new manager takes over, update the contact information with the water provider. The notices go where the account says.
### Testing without cutting water to residents
A test briefly closes the assembly's shutoff valves. On the main service of a complex, that can mean a short water outage for every unit. Plan it for a weekday morning and post notice to residents ahead of time.
Big buildings sometimes avoid the outage with two assemblies side by side. Scottsdale requires parallel assemblies when a customer "requires a continuous water supply," so one stays in service while the other is tested or repaired (Revised Code 49-63). If your property can't lose water at all, such as a senior living building, ask the city's backflow program whether a parallel setup makes sense before the next replacement.
### A few cases that trip up property managers
The irrigation contractor replaced a valve. Swapping a PVB is still a backflow assembly installation. In Phoenix, the customer must get a permit "for the installation of any backflow prevention assembly," and the new assembly needs a passing test.
A condo association took over from the developer. The assemblies stay on the water provider's records for the property, and Phoenix keeps a backflow inventory for each one. The HOA inherits the test dates, even if nobody handed over the old reports.
The complex added a booster pump. Adding a pump or a storage tank can move a building into a category that needs an assembly, even if it didn't before. Check with the city's backflow program when the plans are drawn.
How to get organized
Start with an inventory. Walk the property with last year's reports and match each serial number to a location: meters, irrigation, pools, fire risers. Then set one test date a month before the earliest due date, and have the tester file every report at once.
For where each Valley provider takes reports, see where to send backflow test reports in the Phoenix area. If you can't find an assembly on the property, where to find your backflow preventer shows what to look for. And if a test fails, what happens after a backflow assembly fails its test walks through the repair and retest.
HQ Plumbing & Air tests and repairs backflow assemblies on domestic water and irrigation lines at apartment and condo properties, and repairs underground fire lines. Free estimates, upfront pricing.