Backflow testing and repair in Aurora, CO

Backflow happens when pressure in the city supply drops, from a main break or heavy firefighting draw, and water in your pipes reverses direction. Without protection, water sitting in sprinkler lines, which can carry fertilizer, weed killer and soil bacteria, could be siphoned back toward the public system. The assembly's check valves are what stop it.

During a test we connect a differential pressure gauge to the test cocks, close the shutoffs in the right order and measure whether each check valve holds and, on reduced pressure units, whether the relief valve opens at the correct point. The numbers are recorded and either pass or fail. A test takes minutes when the device is accessible and in good shape.

Most failures are mechanical and repairable. Grit lodges under a check seat, a rubber disc hardens, a spring weakens or a relief valve diaphragm tears. We isolate the device, open it up, clean the seats and install the manufacturer's repair kit. Then we retest, because only a passing result after the repair counts.

Replacement makes more sense when the body is cracked, the device is obsolete and parts are not available, or freeze damage has split a bonnet or the bronze housing. We tell you which situation you are in before any work starts, with the price for each, so you can decide whether a rebuild or a new assembly is the better buy.

Most homeowner backflow preventers sit outside on a riser near the foundation, where they take the full force of winter wind. When the system is shut down in fall, the isolation valve upstream should be closed, the test cocks opened and the device drained so no water is left in the body to expand and crack it.

We can do that winterizing step during a fall visit, or show you how so you can handle it yourself each year. An insulated cover over the assembly helps during an early cold snap, but it does not replace draining. A device full of water will still crack under a cover once the temperature stays low for long enough.