Often, yes. In Phoenix, tenant improvements and changes in occupancy go through the same backflow review as new construction, and the city can require an assembly as a condition of the building permit. A new use with a higher hazard, like a restaurant, clinic or car wash, can need an RP at the service plus point-of-use devices.
How Phoenix handles a new tenant
Phoenix's backflow guidance, TRT 00635, spells out when the city reviews backflow protection. It treats a tenant space like new work: "NEW CONSTRUCTION includes all new buildings, additions, remodeling, tenant improvements, changes in occupancy and new water services for existing properties." For all of those, city staff apply the backflow rules of the Phoenix Plumbing Code and City Code Chapter 37 "as part of the standard plan review, permit issuance and inspection process."
The permit is the lever. The Planning and Development Director "shall, as a condition of issuance of any building permit, require installation of appropriate backflow prevention." The same director decides "whether a facility is a listed facility or activity" that needs protection, and decides "the type and location of all backflow prevention assemblies."
Once a required assembly goes in, the paperwork starts. The owner must submit the original certified test report for the city's backflow inventory, then send annual test reports after that.
### Uses that need an assembly in Phoenix
Phoenix's list of facilities that need an approved backflow method applies to "new services and existing services." A few entries catch many tenant changes:
| New use | Method Phoenix requires |
|---|---|
| Hospitals, medical buildings, clinics, nursing homes, mortuaries | Air gap or RP |
| Veterinary hospitals and animal grooming shops | Air gap or RP |
| Car wash facilities | Air gap or RP |
| Food processing plants and canneries | Air gap or RP |
| Schools and colleges with laboratories | Air gap or RP |
| Retail shopping centers, strip malls and shell buildings where one service supplies more than one tenant | RP |
The shopping center entry has an exception for existing centers "unless a specific hazard is identified." A new tenant with a hazardous use is exactly how a hazard gets identified. For anything not on the list, the director decides "on a case by case basis."
Mesa and Scottsdale work the same way
Other Valley cities key the device to the use too.
Mesa requires an RP on "Buildings or properties used for commercial or industrial purposes, where one service connection supplies multiple tenants or occupants of the building," and on shell buildings (City Code 8-1-8). Inside the space, "All equipment or appliances connected to a customer water system will be subject to evaluation for cross-connection potential and the degree of hazard" (City Code 8-1-9). So a new tenant's equipment, such as a soda system, dental chairs or a boiler, gets its own point-of-use device from Mesa's list.
Mesa also ties fire sprinkler protection to occupancy. An existing fire system with only a detector or alarm check valve can stay as it is until certain events happen. One of them is "A change in occupancy results in a more hazardous classification as determined by the City under the Fire Code," which triggers an upgrade to a double check assembly.
Scottsdale presumes a hazard whenever a listed use is present, and requires the assembly for that use "at each service connection for that premises" (Revised Code 49-62). Its list includes "Any premises where a cross-connection is maintained" and "Shopping centers served by master meters," both RP. Scottsdale also asks account holders to "notify the City of any change in mailing address, occupancy, or ownership within fifteen (15) days after such change occurs" (Revised Code 49-22).
Common tenant changes and what they trigger
Retail to restaurant. The biggest jump. A restaurant adds a soda carbonator, dishwashers, ice machines and chemical dispensers, each with its own device. If the center has one service for several tenants, Phoenix and Mesa expect an RP at the service as well.
Office to medical or dental. Phoenix lists medical buildings and clinics (air gap or RP). Mesa's point-of-use list puts an RP on dental chairs, autoclaves and sterilizers. On the drain side, a general dentistry office also needs an amalgam separator under federal rules; see dental office amalgam separators.
Retail to salon or spa. Mesa's point-of-use list covers shampoo basins (a vacuum breaker) and pedicure stations (an air gap, PVB, RP or SVB). Mesa allows one point-of-use assembly to protect "a group of similar pieces of equipment, such as pedicure stations," where the department approves it, which can save a device per chair. On the drain side, a new salon should also plan for a hair interceptor at each shampoo bowl.
Warehouse to light manufacturing. Process water, chemical tanks or plating can each move the building into an RP category on all three cities' lists.
Same use, new owner. Usually no new device, but the test schedule carries over. The new owner inherits the annual test and report on every existing assembly.
### Who pays and who owns it
The codes put the duty on the customer, the party responsible for the water system. Phoenix says the customer's responsibility "starts at the point of service delivery from the public potable water system and includes all water piping systems," and the customer must "properly locate, install, test and maintain each backflow prevention assembly." A lease can split the cost between landlord and tenant however the parties agree, but the city holds the customer to the code whatever the lease says.
Put it in the lease. Say who pays for any backflow assembly the tenant's use requires, and who books and pays for the yearly test. It's much easier to agree before the build-out than after the plan reviewer asks for an RP.
If you disagree with a decision, Phoenix has a path. Staff decisions on "the need for backflow prevention assemblies, the type of assembly, the installation standards, or the required location" can be appealed to the Building Official, and from there to the Development Advisory Board (TRT 00635).
What to do before you sign or submit plans
- 1Name the use. Match the new use against your city's list. If it appears, plan on the device it names.
- 2List the equipment. Every piece that connects to water, from ice machines to autoclaves, may need its own device.
- 3Check the meter. Find out whether the tenant space shares a service with other tenants. A shared service is its own trigger in Phoenix and Mesa.
- 4Ask early. In Phoenix, call the Backflow Prevention Program at 602-534-2140 before you finalize plans. If the city refers an existing service for review, the owner can instead ask it to evaluate the internal plumbing, for a plan review fee, to show the property already complies.
- 5Budget for the test. Arizona's backflow rule, A.A.C. R18-4-215, requires required assemblies to be tested at least once a year by a certified tester, starting right after installation.
For restaurant equipment specifically, see whether a soda or ice machine needs a backflow preventer. To choose between the two main assemblies, read RPZ vs double check backflow preventers. And once the assembly is in, where to send backflow test reports in the Phoenix area covers the paperwork.
HQ Plumbing & Air tests and repairs backflow assemblies on commercial domestic water and irrigation lines. Free estimates, upfront pricing.
Backflow is one of several systems to review at purchase, as covered in what plumbing to check before buying a commercial building in Phoenix.