Guide

Backflow Theft Prevention: Why Brass Assemblies Get Stolen and What Helps

October 30, 20269 min readBy The Backflow Depot, Rocklin CA

Backflow theft prevention comes down to two things: make the assembly harder to take, and make it worth less to a thief. Brass and copper backflow preventers get cut out and sold for scrap, and the owner is left with no water, a repair bill and a device that has to be replaced and retested. Utilities recommend layers: paint, a locked cage, signs and, where the size and the water purveyor allow it, an approved assembly with less metal in it, such as ARI's composite DC501 and RP501.

This guide is for facility managers, property managers, plumbers and contractors: why backflow preventers get stolen, what water districts advise, what to do if yours is gone, and where composite assemblies fit.

Why do people steal backflow preventers?

For the metal. Water utilities and police describe thieves cutting brass and copper assemblies off the pipe and selling them to scrap and recycling yards (EVMWD flyer, 2024; KMPH, Dec 27, 2024).

The math is lopsided. The scrap value is small next to what the owner pays:

Source (date)	Scrap value per unit	Cost to the owner or utility
EVMWD flyer (2024)	about $60	new or replacement units can cost more than $850
23ABC Bakersfield (Jun 30, 2023)	$25 to $30	about $980 wholesale; one replacement estimate of $2,200
City of Glendale, AZ brochure (2020)	about $40 to $100	$1,200 to $2,000 for a new or replacement unit
Coachella Valley Water District	not stated	about $1,400 total cost to the district per stolen device

In Houston, recyclers put brass at about $2 to $3.50 a pound in July 2026 (KPRC Click2Houston, Jul 29, 2026). These figures are local and dated. Your own costs depend on size, type, labor and your water purveyor's rules.

Where backflow preventer theft has been reported

Backflow preventer theft shows up in local news and utility notices across the West and Southwest. There is no national count. Here is what local sources have reported:

Phoenix, AZ: police reported 88 backflow valve thefts in 2023 and 200 in 2024, and said there had been no spike so far in 2025. One theft left about 200 mobile-home residents without water for hours in 110 F heat (ABC15, Jul 29, 2025).
North Las Vegas, NV: at least 4 devices were stolen at one shopping center, with about $10,000 in damage. At least 8 businesses lost water and a dental office closed (Hoodline, citing KLAS 8 News Now, Oct 13, 2026).
Kingwood (Houston), TX: the third theft at one property. The thief broke through a protective cage, water ran for 7 hours, and repairs were estimated at $4,000 to $5,000 (KPRC Click2Houston, Jul 29, 2026).
Douglas County, CO: two suspects were arrested in February 2026 with four brass backflow valves cut from supply pipes. The sheriff valued them at $1,000 to $2,000 each (Douglas County Sheriff's Office, Feb 2026).
Santa Maria, CA: one business park had about a dozen backflows stolen in a week, about $10,000 to replace (KEYT, Sep 30, 2024).
Bakersfield, CA: a plumber found 6 backflows cut out on one road in a day and 4 more the next. One business lost about $1,500 in sales (23ABC, Jun 30, 2023).
San Antonio, TX: a man was arrested for cutting brass backflow preventers almost daily in March 2026 (KSAT, Apr 3, 2026).

Coachella Valley Water District says backflow devices are the equipment most often stolen from the district (CVWD).

Why a stolen backflow is more than a plumbing bill

A backflow preventer keeps water from the property flowing back into the public supply. When it is gone, that protection is gone until a new assembly is installed and passes its test. EPA's compilation found 459 backflow incidents that caused an estimated 12,093 illnesses from 1970 to 2001 (EPA issue paper). Those incidents were not thefts. They show what the device is there to prevent, and why a missing one can risk contamination.

The rules put the cost on the owner:

Several utilities say repair and replacement is the property owner's responsibility (EVMWD; Rowland Water District; City of Glendale, AZ).
Rowland Water District warns you may be without water until the device is "replaced, inspected, and certified" (RWD, Mar 18, 2025).
In California, an assembly must be field tested by a certified tester after installation or repair, and the water system must receive a passing test before it gives continuous service to a newly installed assembly (State Water Board CCCPH, section 3.3.3).
Santa Margarita Water District's 2025 plan says that if an assembly is missing or stolen, the district notifies the owner and may issue citations or terminate service if it is not resolved (SMWD CCCMP, Jun 4, 2025).

Part of why these assemblies are easy to reach is where the rules put them. California's handbook requires RP assemblies 12 to 36 inches above grade, and DC assemblies installed after adoption follow the same rule unless the water system approves a below-ground install (CCCPH, section 3.3.2).

Backflow theft prevention: what water districts recommend

No single step stops every theft. Kingwood shows a cage can be broken. Utilities recommend stacking several:

Paint or coat it. EMWD suggests painting and camouflaging the device while keeping 1 foot of clearance (EMWD). Glendale, AZ suggests painting it blue or coating it with truck-bed liner, and Rio Rancho, NM suggests several coats of white paint (Glendale brochure; Rio Rancho).
Cage it and anchor it. EVMWD recommends a ground-mounted cage spot-welded to the bolts (EVMWD). Rowland Water District requires enclosures on devices 2 inch and below (RWD). See our backflow enclosures and cages.
Lock it. Walnut Valley Water District rates a cage as "Good" and a shutoff valve lock as "Best" (WVWD flyer, 2024). EVMWD adds a hockey-puck lock or lock guard so bolt cutters cannot reach the lock (EVMWD).
Sign and mark it. EVMWD suggests labeling the device and posting a warning sign. Rio Rancho adds ownership marks, landscaping or a barrier wall (EVMWD; Rio Rancho).
Use less metal. EMWD advises "installing a device with less metal," noting some approved models are less valuable to thieves (EMWD). EVMWD says to consider a device with "considerably fewer brass components" (EVMWD).
Keep the tester's access. EMWD reminds owners that a locking enclosure still has to let the certified tester in for the annual test (EMWD).

Hardware works best together. CVWD says devices it replaced with anti-theft hardware "rarely suffer a repeat theft" (CVWD). Our freeze bag vs heated enclosure guide covers how a locking cage fits with winter protection.

Where ARI composite backflow preventers fit

Walnut Valley Water District lists a low-scrap-value body as an option and says that kind of backflow "is of no use to thieves as there is no value in the materials from a recycling / scrap standpoint" (WVWD flyer, 2024). That is about scrap value. It does not mean the assembly cannot be stolen or vandalized, so keep the cage and lock.

ARI makes two composite assemblies that fit this approach:

ARI DC501 double check. ARI's DC-501 spec sheet lists the body, cover and band as reinforced nylon, with stainless steel bolts and lead-free brass at the inlet ball valve and test cock. It lists ASSE 1015, NSF/ANSI 61 and NSF/ANSI 372, a 150 psi working pressure and NPT threads (ARI DC-501 spec sheet). Sizes: 1" ARI DC501, 1 1/2" ARI DC501, 2" ARI DC501.
ARI RP501 reduced pressure. Aquestia lists the RP-501 under ASSE 1013 and NSF/ANSI 61 (Aquestia RP-501). An older ARI RP-501 spec sheet lists a glass-reinforced polyamide body and cover with stainless steel springs (RP-501 spec sheet). Sizes: 1" ARI RP501, 1 1/2" ARI RP501, 2" ARI RP501.

You can see every ARI product we carry, including parts, in our ARI collection.

USC approval. Both appear on the USC Foundation for Cross-Connection Control and Hydraulic Research list of approved assemblies dated Oct 1, 2026, in 1/2 to 2 inch, horizontal orientation only (USC FCCCHR list). A 2001 USC notice saying no ARI assemblies were approved still circulates online. The current list supersedes it.

Your water purveyor decides. USC listing is not the same as local acceptance. Each water purveyor decides which assemblies it accepts, so confirm the model with yours before you order or install.

Where composite assemblies do not fit

Over 2 inch. ARI's USC approval stops at 2 inch. Fire-service lines and services of 2 1/2 inch and up need other assemblies.
Vertical installs. USC approves these assemblies for horizontal orientation only, and installing in an orientation not listed voids the approval (USC FCCCHR list).
Hot water. Unless the maker says otherwise, USC-listed assemblies are for cold potable water below 110 F (USC FCCCHR list).
Not every ARI model. This guide covers the DC501 and RP501, which USC lists with integral shutoffs. The ARI DC500 and RP500 are listed with separate shutoff valves, so check the model on the tag (USC FCCCHR list).
Not a replacement for a cage. Every utility above that suggests a less-metal device also recommends a cage or locking enclosure.

What to do if your backflow preventer is stolen

Shut off the upstream supply valve to stop the water (EVMWD; Glendale brochure).
File a police report, then report it to your water purveyor (Pasadena Water and Power; Rio Rancho).
Replace and retest. A certified tester has to test the new assembly before service is restored in California (CCCPH, section 3.3.3). Read the tag on any remaining parts first so the size is right (how to read a backflow tag).
Add protection when you replace it. A cage, a lock and, at 2 inch and under where your purveyor allows it, a composite assembly.

If only part of the assembly was damaged and the body is intact, repair parts may get it back in service.

What the law says about scrap buyers

Laws exist, but they vary. California Business and Professions Code 21609.1 bars junk dealers and recyclers from possessing backflow devices owned or previously owned by a public agency, city, special district or regulated private utility without written certification. It was amended effective Jan 1, 2026 (Cal. B&P Code 21609.1). In Nevada, Clark County passed a 2024 ordinance banning cash payments for scrap copper (Hoodline, Oct 13, 2026). Those rules target the buyers. The cage, the lock and the choice of assembly are what you control.

FAQ

How much does it cost to replace a backflow?

It depends on size, type and labor. Published ranges include more than $850 for a new or replacement unit (EVMWD, 2024), $1,200 to $2,000 (Glendale, AZ, 2020) and a $4,000 to $5,000 repair estimate after one Houston-area theft (KPRC, Jul 29, 2026).

Is an anti theft backflow cage enough?

It helps, and some districts require one. In Kingwood a thief broke through a protective cage (KPRC), which is why utilities pair the cage with a backflow cage lock, lock guards, paint and signs.

Are composite backflow preventers approved?

The ARI DC501 and RP501 are on the USC approved list dated Oct 1, 2026, for 1/2 to 2 inch, horizontal only (USC FCCCHR list). Your water purveyor decides what it accepts, so check with them first.

Sources: ABC15, Jul 29, 2025 · Hoodline (citing KLAS 8 News Now), Oct 13, 2026 · KPRC Click2Houston, Jul 29, 2026 · Douglas County Sheriff's Office, Feb 2026 · KEYT, Sep 30, 2024 · 23ABC (KERO), Jun 30, 2023 · KSAT, Apr 3, 2026 · KMPH, Dec 27, 2024 · Coachella Valley Water District · Elsinore Valley MWD flyer, 2024 · Eastern Municipal Water District · Walnut Valley Water District flyer, 2024 · City of Glendale, AZ brochure, 2020 · Rowland Water District, Mar 18, 2025 · City of Rio Rancho, NM · Pasadena Water and Power · California State Water Board, Cross-Connection Control Policy Handbook (rev. Apr 21, 2026) · Santa Margarita Water District CCCMP, Jun 4, 2025 · California B&P Code 21609.1 · US EPA, cross-connection and backflow issue paper · USC FCCCHR List of Approved Backflow Prevention Assemblies, Oct 1, 2026 · ARI DC-501 spec sheet · Aquestia, ARI RP-501 · ARI RP-501 spec sheet (older)