Shut off the water upstream of the missing backflow preventer, then report the theft to your water provider and the police. The replacement needs a city permit, must be an approved assembly, and has to pass a test by a certified tester before it goes back in service. Never pipe straight across the gap.
The first hour: stop the water and report it
Glendale's water department puts out a brochure on exactly this, and its emergency steps are short. If the device is stolen: "Turn off water supply valve upstream of backflow device." Then report the theft to the city's water services and to the police. The same steps work anywhere in the Valley.
- 1Close the valve upstream. That's the valve between the water meter and where the assembly used to be. If the thieves cut the pipe above every valve you can reach, call your water provider's customer service line and ask them to shut the service.
- 2Call the water provider. Tell them the assembly is gone and the service is off. They'll want to know, since the assembly is on their records, and they can tell you what they need before water goes back on.
- 3File a police report. Use the non-emergency line. Give them the make, model, size and serial number.
- 4Find the serial number. Your last test report has it. Phoenix's test report form has fields for the manufacturer, size, model number and serial number, so pull the last one from your files or ask your tester for a copy.
- 5Take photos of the cut pipe and the empty spot before anyone touches it. You'll want them for the police report and for your records.
If the missing assembly was on a fire line, call your fire sprinkler contractor right away, since the sprinkler system may be without water until it's replaced.
Why do thieves bother? Glendale's brochure answers in five words: "Thieves take them for their copper and brass." Arizona law tries to close that market. Under A.R.S. 44-1642.01, a scrap metal dealer "shall not knowingly purchase" several items, including "Brass or bronze commercial potable water backflow preventer valves that are valves commonly used to prevent backflow of potable water into municipal domestic water service systems from commercial structures." A violation is a class 1 misdemeanor. Marking your assembly (more on that below) makes it easier for a dealer or an officer to recognize one.
Don't pipe across the gap
The tempting fix is a straight piece of pipe to get the water back on. Don't. Every Valley code treats that as a serious violation, because it leaves the public water supply with no protection from your building.
- Tempe says flatly: "No bypass shall be installed around backflow prevention assemblies" (City Code 33-104).
- Mesa's definition of a cross-connection includes "Bypass arrangements, jumper connections, removable sections" (City Code 8-1-1), and Mesa can terminate service when backflow protection "has been removed or bypassed" (City Code 8-1-13).
- Phoenix can terminate water when a customer "Removes or bypasses a required backflow prevention assembly without the prior approval of the Planning and Development Director" (City Code 37-146).
- Scottsdale can disconnect the supply line when an assembly has been "bypassed or removed" and the problem isn't fixed in the time the notice gives (Revised Code 49-66).
The plumbing code backs this up. Phoenix's tester guidance quotes it: "No device or assembly shall be removed from use or relocated or other device or assembly substituted, without the approval of the Authority Having Jurisdiction" (TRT 00636).
So if the building can't wait, call the city's backflow office first and ask what it will accept in the meantime. In Phoenix, that's the Backflow Prevention Program at 602-534-2140. In Mesa, it's 480-644-6462 or backflow@mesaaz.gov. Get any approval in writing.
Who pays for the replacement? Glendale's brochure notes that backflow preventers are the property owner's responsibility for repair and replacement. The codes in Phoenix, Mesa, Scottsdale and Tempe put it on the water customer or user, which can be the owner or the tenant. If you lease, see who pays for backflow testing and repairs: landlord or tenant.
Replacing it: permit, install, test, report
A replacement is treated like a new installation. Here's how it works in the big Valley cities.
Phoenix. "The customer shall obtain a permit from the Planning and Development Department for the installation of any backflow prevention assembly" (City Code 37-143). The test report asks the tester to "Provide the plumbing permit number if this is a new assembly or replacement assembly," and, "If this assembly is a replacement for another assembly, provide the serial number of the assembly that was replaced" (TRT 00335). That's one more reason to keep the old serial number handy. Phoenix also wants a report on the new unit: "Original test report(s) are required on all testable backflow assemblies, which include new backflow installations, relocated backflow preventers, replacement of a backflow preventer" (TRT 00641).
Scottsdale. "A separate permit shall be obtained for each required backflow prevention assembly to be installed, including replacement" (Revised Code 49-68). The user must also "perform any necessary repairs, including replacement of the assembly, if necessary" (Revised Code 49-65). Scottsdale's installation site plan form asks for both the existing and the proposed assembly, and notes that "Site plans will be reviewed within 5 business days."
Mesa. Mesa's backflow page says "Permits are required to install these assemblies. Permits are issued by Mesa." After any "overhaul, repair, or replacement," a recognized tester "must retest the backflow protection within 24 hours" (City Code 8-1-11). And when a customer finds an assembly isn't working between tests, Mesa City Code 8-1-11 gives "15 calendar days of such discovery" to repair or replace it.
Tempe. "Following the repair, repiping, overhaul or relocation of an assembly, the user shall have it inspected by the department and tested by a certified tester" (City Code 33-107).
Statewide, Arizona's backflow rule sets the floor: "An assembly shall not be placed in service unless it has been tested and is functioning as designed." So the new unit gets tested the day it goes in, not at the next yearly date.
Two more things to get right. Size: Mesa says installed assemblies "must have a diameter at least equal to the cross-sectional diameter of the service connection," and Scottsdale says the same in its own words. Type: replace an RP with an RP and a double check with a double check, unless the city says otherwise. The city chose that type for the hazard on your property. Our guide to RPZ vs double check backflow preventers explains the difference.
| Step | Phoenix | Mesa | Scottsdale | Tempe |
|---|---|---|---|---|
| Permit for the replacement | Yes, from Planning and Development | Yes, issued by Mesa | Yes, a separate permit per assembly | Inspection by the department after the work |
| Test after install | Yes, original report required | Within 24 hours | Yes, records within 7 days | Yes, by a certified tester |
| Report detail | Permit number and replaced serial number | Report within 7 calendar days | On Division-approved forms | On department-approved forms |
Fire line assemblies are different. In Phoenix, fire line tests "must be performed by a certified tester who is also permitted by the City Fire Marshal to test fire lines or fire sprinkler systems" (City Code 37-143). Scottsdale adds that before "installing or replacing a backflow prevention assembly on an existing sprinkler system, the sprinkler system must be tested and determined able to meet National Fire Protection Association Standard 13 minimum flow calculations" (Revised Code 49-64). That replacement and test go through a fire-licensed contractor. For who can test the rest, see who can test backflow assemblies in Arizona.
Make the next one harder to steal
Glendale's brochure lists deterrents like these, and they're all reasonable for a commercial property:
- Paint, label or coat it. Glendale suggests painting the assembly blue or spraying it with truck bed liner to cut its scrap value, and stamping or labeling the metal in several places with a code you'd recognize.
- Cage it. Glendale suggests a protective cage around the assembly and says "The cage should be secured or mounted to the ground." It also suggests having the cage spot-welded to the bolts.
- Lock it well. Glendale recommends a high-quality lock, notes that hockey puck style locks work best for cages without lock guards, and says "Lock guards protect locks from bolt cutter access."
- Post a warning sign mentioning security and prosecution.
- Use a heavy-duty enclosure box for industrial or high-security sites.
- Screen it with landscaping so it's less obvious from the street.
Here's the catch. Whatever you add still has to meet the city's installation rules. Phoenix says "All assemblies must be accessible for testing and maintenance," and "A reduced pressure principle assembly or double check valve assembly may not be installed in a basement, meter box, pit, or vault" (City Code 37-144). Tempe says "Reduced pressure principle assemblies shall be installed above ground" (City Code 33-104). Scottsdale wants an "accessible location as close as possible to the service connection with proper clearances above the ground" per its standard details (Revised Code 49-63). So you can't hide an RP in a buried vault or move it behind the building to get it out of sight. Moving it counts as relocation, which needs city approval and a new test.
In practice, that means a few choices. Pick a cage or enclosure sized so the tester can reach every test cock and valve. Give your tester a key, or plan to meet them. An RP dumps water from its relief valve when it's working as designed, so choose an enclosure that drains, and keep the serial plate and test tags readable if you paint. Ask the city whether it has a standard detail for enclosures before you buy one. If you're not sure where your assembly is or what type it is, start with where your backflow preventer is and what it looks like.
HQ Plumbing & Air replaces and tests backflow assemblies on domestic water and irrigation lines and repairs underground fire lines, 24/7, with upfront pricing and free estimates.
Enclosures are also discussed in what an RPZ hot box is. If the building is empty, protecting plumbing in a vacant commercial building covers locking up assemblies and valves.