Tempe City Code 33-103 and 33-104: backflow assemblies on plans and how to install them

Section 33-103(c) is the plan rule. It says: "Assemblies shall be specified and located on the construction plans for all new buildings, additions with new services, and changes of use or occupancy of existing buildings where required by Section 33-105. Approval shall be obtained prior to issuance of the building permit." Paragraph (a) adds that assemblies are installed by and at the expense of the user. Paragraph (b) says the department can approve an assembly that meets the criteria in 33-106(b) if the manufacturer has a local parts and service center.

Section 33-104 covers installation:

• Location (a): at the service connection or near the property line, always before the first branch line, in an accessible spot the department approves.
• Size (b): at least the same cross-sectional area as the water service or meter. If the water cannot be shut off for testing, two sets go in parallel.
• No bypass (c): nothing may be plumbed around the assembly.
• Double check assemblies (d): installed to the city's standard details, and they may go below ground in a vault only if the department approves it in writing, case by case.
• Reduced pressure assemblies (e): installed to the standard details, above ground.
• Valves and test cocks (f): resilient seated shutoff valves upstream and downstream and resilient seated test cocks so the tester can connect gauges.

Section 33-107(d) then ties the last step to the certificate of occupancy: the tester's results go to Community Development with a request for inspection approval before the certificate can be issued.

• Change of use or occupancy: a new kind of business in an existing space, such as an office becoming a restaurant. The code does not define it. Our reading is that a like-for-like tenant swap is not a change of use, but plan review makes the call.
• Additions with new services: an addition that gets its own water connection. An addition fed from the existing service is not named.
• Approved assembly: one that meets 33-106, which points to AWWA C506 and the USC Foundation for Cross-Connection Control and Hydraulic Research listing, or another third-party certifier the department accepts.

It covers new commercial buildings, additions with new services and changes of use where 33-105 requires an assembly. It does not cover building permits applied for before the article took effect, except through 33-110. A house used only as a house is outside the program, according to the city's Backflow FAQ.

A new medical office. The designer draws the plumbing and leaves the assembly for later. The city will not issue the building permit until the assembly is on the plans and approved, so the drawing set goes back.

A tight utility room. The plans put the RP in a below-grade vault to save floor space. Section 33-104(e) requires RP assemblies above ground. The layout fails and gets redrawn.

The edge case: a vault for a double check. Section 33-104(d) allows a double check in a vault with written approval. Tempe's plumbing code amendment, IPC 608.8.1, says backflow prevention devices "shall not be installed in pits, underground vaults, or submerged locations." The two texts do not reconcile on their face, so treat a vault as a written-approval request that can be refused, not a default.

1. 1Pick the assembly type from 33-105 for your premises.
2. 2Show the assembly, its size and its location on the plumbing plans, before the first branch line and outside any vault.
3. 3Choose a model from the department's approved list.
4. 4Submit the plans with the building permit application. Wait for the department's approval before the permit issues.
5. 5After installation, have a certified tester test it and send the results to Community Development with an inspection request. The certificate of occupancy waits on this.
6. 6Note the date of the first inspection. The yearly test runs from that anniversary, and Environmental Services (480-350-2678) tracks it.

• "Backflow is a punch-list item." In Tempe it is a plan item, and the building permit waits on it.
• "I can bury it to keep it out of sight." RP assemblies go above ground, and IPC 608.8.1 bars pits, vaults and submerged locations.
• "Any listed device is fine." It must meet 33-106 and have a local parts and service center.
• "I can bypass it during a shutdown." Section 33-104(c) bans a bypass. Use two parallel assemblies if the water cannot go off.