Backflow cages are metal enclosures designed to cover above-ground backflow prevention devices. These cages are intended to deter tampering and theft while leaving the equipment accessible for maintenance.
Cages are typically used on backflow prevention devices 3-inches and smaller, such as irrigation and sprinkler system installations. Their relatively simple construction makes them inexpensive to produce in small sizes, which has contributed to their widespread use. Backflow preventer cages are especially common in warmer climates like Arizona and Florida, where there's often an assumption that freeze protection is unnecessary.
However, cages offer no freeze protection for backflow devices and cannot be relied upon during winter. Plus, metal theft still occurs because vandals can easily see the pipes and use bolt cutters on locks. For these reasons, backflow preventer enclosures are increasingly moving away from cages.
Protection: Cages are typically made of powder-coated steel with a locking mechanism. They have no insulation and therefore no frost or freeze protection, though they're sometimes used in conjunction with insulated bags. Cages provide limited protection from theft and vandalism.
Sizes (approximate): 24" x 24" to 60" x 60"
They're typically chosen for backflow assemblies 2-inches and smaller, though larger sizes exist.
Materials: Steel or heavy-duty metal, often with powder-coated finishes for rust resistance
Colors: Green, bare metal and tan
Prices: $300 to $3,500 depending on size, style and features and installation costs per region due to permits and labor. This cost depends on factors like materials used, size and brand.
Backflow preventer theft surged during the Great Recession as the value of copper, brass and galvanized steel attracted thieves. Areas that previously required no enclosures suddenly did. Companies and municipalities turned to cages as a fast, low-cost countermeasure. Multiple cage manufacturers entered the market to meet demand.
The economics have since shifted. The cost of manufacturing aluminum enclosures has come down significantly, and ASSE 1060-compliant enclosures are now priced competitively with cages when total lifecycle cost is considered. But the cage habit has persisted, and for engineers and jurisdictions writing specifications, that persistence carries real risk.
The case against specifying cages goes well beyond aesthetics. For design engineers and water jurisdictions, cages present compliance exposure, liability risks and operational problems that aluminum enclosures avoid entirely. Here are the reasons why cages are outdated.
The industry benchmark for backflow enclosures is ASSE 1060, first established in 1996 and updated most recently in 2017. This standard sets minimum performance thresholds for freeze protection, drainage, access and security. Backflow cages do not meet ASSE 1060 requirements.
ASSE 1060 Class I enclosures are heated and designed to maintain internal temperatures of 40°F even when outdoor temperatures reach -30°F. A powder-coated steel backflow preventer cage open to the elements cannot come close to that standard. Engineers who specify cages where an ASSE 1060 enclosure is required — or where the trend is clearly moving in that direction — are taking on a specification risk that is difficult to defend.
Several jurisdictions across the United States have updated their codes or engineering standards to require insulated or heated backflow enclosures instead of cages or vaults. Examples include:
These examples reflect a broader trend among water jurisdictions to move away from cages and vaults in favor of secure, insulated above-ground enclosures that meet ASSE 1060 performance standards.
Water jurisdictions that allow or mandate cages may be accepting liability they haven't fully accounted for. When a cage-protected assembly freezes and fails, or is stolen and a cross-connection event follows, the chain of responsibility runs back to the specification. Jurisdictions that have not updated their standard details to reflect current enclosure standards are particularly exposed.
For engineers of record, specifying a cage where an ASSE 1060 enclosure would have prevented a failure is a defensibility problem. The USC Foundation for Cross-Connection Control and Hydraulic Research urges jurisdictions to avoid below-grade installations, and has for nearly two decades — the same institutional pressure is building around cage installations in freeze-prone regions.
This is the most consequential technical limitation of cages, and it is not limited to northern climates. Freeze events have caused widespread backflow device damage across the Sun Belt in recent years:
Class 1 ASSE 1060-certified enclosures with slab-mounted heaters are built for freeze protection. Regardless of baseline climate conditions, the frequency and severity of unexpected freeze events makes thermal protection a standard, not an option. Engineers and jurisdictions that continue specifying cages in any region other than the extreme Southwest are accepting an actuarial risk that enclosures eliminate.
An open cage sitting on grade has no drainage design. Stormwater, irrigation runoff and contaminants can pool around the assembly, and because the cage is open to the environment, that contaminated water has direct access to test cocks and valve components. This is not a theoretical risk. Many testers report encountering standing water or debris around caged assemblies during routine checks.
For water jurisdictions that operate cross-connection control programs, this is a compliance problem, not just a maintenance inconvenience. Above-ground enclosures certified to ASSE 1060 include drainage requirements that ensure proper water evacuation. The relief valve on an RPZ assembly has a clear path to discharge without contaminating the surrounding environment or creating a submerged test cock scenario.
Backflow prevention devices are made from bronze, copper, cast iron and stainless steel — materials that retain scrap value regardless of market conditions. A cage doesn't conceal the assembly; it frames it. Thieves know exactly what they're looking at.
The bandage fixes that follow cage theft — steel bars, security cameras, painting valves to reduce scrap value — represent both an acknowledgment that cages have failed and an unnecessary compounding of cost. Painting a valve, for example, can clog test cocks and prevent check covers from opening, voiding the manufacturer's warranty and creating the maintenance problems cages were supposed to prevent.
ASSE 1060-certified aluminum enclosures are enclosed, tamper-resistant and fully obscure the assembly inside. A thief has no visual confirmation of what the enclosure contains, and the locking mechanism is designed to resist tampering, not merely slow it down.
Rigid cages present a dilemma for design engineers: a properly sized cage that closely surrounds the assembly restricts the working clearances required for testing and service. An oversized cage that accommodates those clearances is more vulnerable to tampering and theft. There is no good middle ground.
Many jurisdictions require adequate working clearances as part of their building and cross-connection codes. A cage that restricts tester access can put the installation out of compliance. Modular aluminum enclosures, by contrast, are engineered with maintenance in mind. Panels can be removed or doors opened for full access without disassembly or awkward maneuvering.
Standard clearance requirements engineers should account for in any specification include:
Cages are not designed around these clearances. Enclosures sized to ASSE 1060 requirements are.
The cage-versus-enclosure decision is often framed as a cost comparison, but the upfront number is not the full picture. Powder-coated cages rust, fade and corrode. Their functional lifespan tops out around 15 to 20 years under ideal conditions — and those conditions rarely persist outdoors. Marine-grade aluminum enclosures routinely last more than 30 years with minimal maintenance.
The total cost of ownership comparison should account for:
Due to manufacturing efficiencies over the past decade, ASSE 1060 aluminum enclosures are now cost-competitive with steel cages on an upfront basis. When lifecycle factors are included, the enclosure wins decisively.
Property owners and site design teams sometimes push for cages on aesthetic grounds — the assumption being that a cage is less visually intrusive than a box. The opposite is closer to the truth. A cage displays its contents. A closed enclosure conceals them.
Modern aluminum enclosures are available in a range of colors — green, gray, tan and others — that blend with landscaping and site surroundings. Smaller N-type backflow preventers can reduce enclosure size by up to 25 percent compared to traditional configurations. Vinyl wrap graphics allow enclosures adjacent to buildings or entries to be treated as branded design features rather than utility eyesores.
The standard for non-residential backflow enclosures is an ASSE 1060-certified, heated, above-ground aluminum enclosure. Forward-thinking municipalities are codifying this in published standard details — and the engineers who work with those jurisdictions regularly are already specifying this.
Safe-T-Cover works with water jurisdictions and design engineers across the country to develop standard details that support outdoor, above-ground installation of backflow preventers in protective enclosures.
Download the free Standard Details Guide and get:
Need sizing help? Contact our design team to discuss your project.
Jurisdictions are driven by a combination of ASSE 1060 adoption, liability concerns around freeze failures and cross-connection risk, widespread theft and vandalism, and the operational preference of backflow testers for accessible above-ground installations. The pattern is consistent across regions.
The ASSE 1060 standard, created in 1996 and updated in 2017, regulates the backflow enclosure industry. It sets minimum requirements for exterior protection, interior temperature control, locking mechanisms and drainage. Class 1 enclosures are heated and must maintain a minimum internal temperature of 40°F at an ambient outdoor temperature of -30°F. Backflow cages do not meet this standard.
On an upfront basis, ASSE 1060 aluminum enclosures are now cost-competitive with steel cages in most size categories. When lifecycle factors — replacement frequency, supplemental security costs and the cost of freeze or theft events — are included, enclosures are the clear value choice.
Yes, regardless of standard climate conditions. With freeze events occurring across Texas, Florida and throughout the Sun Belt, it can no longer be assumed that an insulated enclosure alone is adequate protection. A slab-mounted heater is the standard recommendation for any ASSE 1060 Class 1 enclosure.
Yes. While standard in-stock enclosures cover the majority of applications, custom enclosures can be designed to exact specifications for larger assemblies, dual-service installations, meter and backflow combinations, or sites with unusual layout constraints. Many jurisdictions are now combining water meters and backflow preventers in a single above-ground enclosure, simplifying installation and speeding up annual testing.
.jpg?width=206&name=MadeInUSA-Icon%20(1).jpg "MadeInUSA-Icon (1)")
