Irrigation systems make watering lawns and gardens easier while saving time. However, weed killers, fertilizers and other contaminants can enter the water system through backward movement of water called "backflow." This backflow can be caused by changes in the water pressure, for example, when firefighters fight a nearby blaze or before City crews repair a broken water main. If a backflow occurs, unprotected irrigation systems could endanger the health of our water supply.
This backwards movement allows the water in your pipes to flow in the opposite direction, into our drinking water supply. This situation is created by a "cross-connection." Cross-connection can occur when your lawn irrigation system is not protected with a backflow prevention assembly.
Contaminants on your lawn may enter the drinking water supply. Some sprinkler heads sit at or below ground level where animals and pets may urinate on them and drop feces, which can contain harmful bacteria. In addition, pesticides from your lawn, stagnant water from non-potable water pipes and bacteria in the soil can be siphoned back and end up in the public water system.
Double Check Valve Assembly
The City of Bremerton's Water Utility requires an approved "double check valve assembly" for irrigation systems to protect the public water supply. This assembly is simply 2 spring-loaded check valves in a row with shut-off valve on either end and test cocks to allow the assembly to be tested for proper operation. The assembly will be installed to protect the public water supply by installing it in the service line to the house "premises isolation" within 2 feet of the water meter. See the drawing (PDF). After the assembly is installed it must be readily accessible for maintenance and testing. All backflow assemblies must be tested by a certified backflow assembly tester when installed, moved or repaired and annually. Irrigation systems without an approved backflow prevention device are in violation of state and local regulations. (WAC 246-290-490.)
All irrigation systems, new and existing, must be equipped with an approved backflow prevention assembly. The city provides safe drinking water, please help keep it safe by ensuring your irrigation system has the proper backflow prevention.