Backflow Enclosures in Chapel Hill, NC

North Carolina winters are mild until they are not. Chapel Hill gets a handful of nights each year cold enough to freeze water sitting in an above-ground backflow assembly, and brass does not survive that. The result is a cracked body, a replacement unit, and a retest.

What OWASA actually requires now

This changed in August 2025, and the change is worth understanding before anyone sells you an enclosure. Assemblies serving domestic purposes only, two inches or smaller, no longer require heat inside the protective housing. And for residential irrigation systems and pools, a protective enclosure is not required for freeze protection at all, provided the assembly is installed with unions and an upstream shutoff so it can be removed for winterization.

That means many Chapel Hill homeowners have a genuine choice: fit an enclosure and leave the assembly in place, or set it up to be removed each winter and stored. Neither is wrong, and the right answer depends on your property and how you use the system.

The trade-off to weigh

Removing the assembly each winter avoids the cost of an enclosure, but it has a consequence for testing. The three-year testing interval available to qualifying year-round irrigation assemblies only applies while the unit stays in service. Take it off for winter, and it must be tested within ten days of going back in — effectively every year. An enclosure that keeps the assembly in place year-round can therefore save you test visits over time.

Where an enclosure is the right call, we fit rated, insulated units sized to the assembly, with proper drainage and access for testing. An enclosure that cannot be opened for a gauge test creates a different problem entirely.

Requirements described here come from OWASA’s August 2025 update to its cross-connection control requirements. Rules change — we confirm what applies to your property before any work.

The irrigation assemblies in Southern Village, Meadowmont, and the newer East 54 builds are typically above ground and exposed, which puts them squarely in the group that needs either an enclosure or winter removal.

Pool and spa assemblies across the older neighbourhoods near downtown and out around Coker Hills and Lake Forest face the same exposure, and are often in more awkward positions where a correctly sized enclosure matters for test access as much as for warmth.

On commercial properties, fire line and larger domestic assemblies usually stay in service year-round by necessity, so an enclosure with proper drainage and access is generally the practical route rather than seasonal removal.