How To Modernize Your Backflow Installation Specs With Free CAD Files

Outdated vault installations, often referred to as pits, are still widely used across the U.S., but they’re no longer the standard of safety, efficiency or compliance. 

As cities like Las Vegas, Arlington and municipalities across New Jersey have already discovered, there’s a better way to protect people, property and potable water: above-ground aluminum enclosures backed by clear backflow preventer installation details.

If you’re still relying on specs pulled from past projects or defaulting to below-grade vaults, it’s time to rethink your approach and adopt more acceptable standards. And we're here to help with free CAD files and a complete Standard Details Guide to accelerate your transition.

Why Above-Ground Backflow Assembly Installations Are Best Practice Now

Above-ground backflow installations, when properly installed, aren’t just safer. They’re smarter. Here’s why more and more municipalities are writing them into their standard details:

1. Avoid Confined Space Hazards

Underground utility vaults are OSHA-classified confined spaces. That means more risk, more crew requirements and more liability when maintenance personnel check relief valves and perform backflow preventer maintenance. In fact, over 1,000 U.S. workers died from confined space injuries between 2011 and 2018. With above-ground enclosures, that risk is eliminated entirely.

2. Eliminate Cross-Connection Threats

Vaults can and do flood. Backflow prevention assemblies installed in a vault are unable to expel runoff and facilitate a dangerous cross-connection. Above-ground enclosures keep the entire system dry, visible and protected from debris. If you're after better cross-connection control, above ground is best.

3. Prevent Costly Water Damage

RPZ valves can discharge hundreds of gallons per minute and drains aren't equipped to handle it. When installed indoors in buildings or below ground, that water flow has nowhere to go, resulting in flooded basements, destroyed equipment and million-dollar lawsuits. A simple above-ground installation mitigates the risk outright.

4. Speed Up Testing and Maintenance

Testing backflow preventers in a vault can be slow, labor-intensive and requires safety compliance. With curbside, above-ground installations, testing becomes a quick, walk-up procedure with the enclosure's removable access panels. Crews can complete more inspections in a day, saving time and money for your department.

What Every Modern Backflow Preventer Enclosure Spec Should Include

Whether you’re updating jurisdiction-wide standards or refining specs for a single project, here are the key design considerations, including diameter, your backflow installation details should address:

Proper Clearance

A good spec includes clear measurements for the space inside and around the enclosure — typically 6–12" between the enclosure and the assembly, and 2’ minimum around the exterior for accessibility.

ASSE 1060 Compliance

This industry standard outlines requirements for drainage, insulation, access panels and tamper resistance. Any spec that doesn’t reference ASSE 1060 is putting your installation — and the water system — at risk.

Real-World Placement Guidance

Your detail should account for finished grade, sightlines, aesthetics and setback zones. Place enclosures near the property line, not directly in front of entrances or obstructing traffic views.

Integrated Aesthetic Considerations

Aluminum enclosures come in a range of colors and even support vinyl wraps. A well-designed spec meets safety standards and helps avoid resistance from manufacturers, architects and property owners by blending into the environment. We recommend putting the water meter inside the enclosure along with the backflow prevention device.

We’ve Already Done the Work For You

Writing all of this into your own custom standard detail set would take days, possibly weeks. That’s why Safe-T-Cover created the Standard Details for Above-Ground Enclosures Guide, including five ready-to-use CAD templates.

Each CAD file is:

• ASSE 1060-compliant
• Designer-friendly and editable in AutoCAD
• Field-tested across multiple jurisdictions
• Accompanied by a printable PDF version
• Optimized for clearances, drainage and aesthetics

What’s Included in the CAD File Set:

1. Backflow Assembly Enclosure (2½”–12”)
2. Fire Line Double Check Detector Assembly
3. Compact N-Pattern Enclosure
4. Irrigation System Enclosure
5. Site Placement Layout for Proper Location and Clearances

These drawings were developed in collaboration with engineers and utility teams in real jurisdictions. They’re not theoretical: They’re practical, tested and proven.

See What’s Already Working in Other Cities

Still not sure if it’s time to update your specs? These municipalities already did:

• Las Vegas Valley Water District saved $60,000 per installation by removing the meter and backflow from vaults and placing both in the same above-ground enclosure.
• Arlington, Tex. became the first city in north-central Texas to publish official above-ground specs for non-residential backflow preventers.
• New Jersey adopted curbside, above-ground enclosures after serious incidents involving underground vaults.

The Best Protection for Backflow Prevention Devices

If your team is still working from vault specs, or if your engineers are stuck drafting new details from scratch, it’s time to skip the guesswork. We're giving away these modern, code-compliant specs because we're passionate about keeping our water supply safe. To us, there's no "high hazard" or "low hazard" classification for backflow installations — if it's not outdoors and above-ground, it's a hazard.

Get the Free CAD Files and Standard Details Guide

Whether you're designing a new commercial project or updating city-wide infrastructure guidelines, these CAD files give you a head start toward safer, smarter water system design.