Backflow assembly installs and repairs in Salem

Water normally moves one way, from the city main into your house. Under certain conditions, such as a water main break or heavy demand from firefighting, pressure in the street can drop below the pressure in your own lines. Without a barrier, water sitting in a sprinkler pipe or boiler loop can be pulled back into the supply.

Sprinkler water carries fertilizer, soil and whatever has collected in the heads. Boiler water carries treatment chemicals. A backflow assembly is a set of check valves that closes when flow reverses. The City of Salem requires these assemblies where a connection poses that risk, and it requires them to be tested once a year.

Back-siphonage and backpressure in plain terms

Back-siphonage happens when street pressure drops and the house side acts like a straw, drawing water backward. A garden hose lying in a bucket of weed killer during a main break is the classic example. Backpressure is the reverse case, when a pump or a heated boiler pushes water at a higher pressure than the city supply.

Either way, the assembly's job is the same: stop water from crossing back over. The type you need depends on how hazardous the water behind it is and how the connection is arranged.

Double check versus reduced pressure assemblies

A double check valve assembly uses two spring-loaded check valves in a row, with shutoff valves and test cocks on each side. It suits many residential irrigation systems where the hazard is lower. A reduced pressure assembly adds a relief valve between the two checks that dumps water out if either check leaks, so it protects against higher hazards.

Reduced pressure assemblies must be installed above ground where the relief port can discharge freely, never in a pit that could flood. Which assembly a system requires is set by the water purveyor, so we confirm the requirement before installing.

• Double check assemblies are common on lawn irrigation and fire sprinkler lines
• Reduced pressure assemblies are used where chemicals or higher hazards are present
• Both have test cocks so a tester can measure each check valve
• Freezing can crack the body or bronze parts, so winter protection matters

How the yearly City of Salem test works

The City of Salem requires each backflow assembly on its system to be tested every year by a tester certified by the Oregon Health Authority. The tester sends the report to the City. Each customer has a compliance month, and the City mails a reminder letter ahead of it.

The City notes that many tests cost about $30 to $50. Our staff do not perform the certified test. What we do is install and repair assemblies, and we can help you set up the yearly test with a certified tester so a failed result can be repaired and retested quickly.

Repairing an assembly that failed its test

Most test failures come from a check valve that will not hold, usually because debris is caught on the seat or the rubber disc has hardened. Rebuilding the assembly with a new kit of discs, springs and seals often brings it back into spec. Cracked bodies, often from freezing, call for a replacement.

After repairs, the assembly has to be retested and the passing result reported. We coordinate timing so the tester can return soon after the work is done.