Cross Connections

Lawn Irrigation Systems
Cross Connection Control for Fire Sprinkler Systems
Single Family Fire Sprinkler Meter Requirements
Single Family Residential 3/4 inch and 1 inch Standard Fire Sprinkler DCVA Connection Detail
Drinking Water Regulations Relating to Cross Connection

The Sammamish Plateau Water and Sewer District is engaged in a program of locating cross-connections between the public water supply and possible sources of contamination. The control of cross connections is accomplished by two basic methods: (1) Inspection and regulation of plumbing or piping systems within premises; and (2) Installation of approved backflow prevention assemblies on water service lines to premises where hazardous cross-connections exist or are likely to occur. The program implements both of these methods.

The Rules and Regulations of the Washington Department of Health require that certain premises install backflow prevention assemblies on the water supply piping as a condition of water service. Backflow prevention assemblies shall be installed within any premises where in the judgment of the Water Department the nature of the activities on the premises or the materials used or stored on the premises present a hazard should a cross connection occur.

The Sammamish Plateau Water and Sewer District require proper installation of a Washington State approved backflow prevention assembly (BFP) on water supply piping which meet the following conditions:

1. Atmospheric Vacuum Breaker (AVB) may be used on a single zone irrigation system, must be installed 6 inches above highest fixture, no shutoff valves allowed downstream, must be inspected by the Water Department, but does not require annual testing.
2. Pressure Vacuum Breaker Assembly (PVBA) may be used on multi-zone irrigation system, must be installed 12 inches above the highest fixture, shutoff valves are allowed downstream, assembly must be tested by a state certified backflow assembly tester, requires annual testing thereafter.
3. Double Check Valve Assembly (DCVA) may be used on multi-zone irrigation system, it protects against backpressure and backsiphonage, required on all pumped or elevated piping systems, which may cause backpressure. May be installed in irrigation box, must be tested by a state certified backflow assembly tester, requires annual testing thereafter.
4. Reduced Pressure Backflow Assembly (RPBA) required on all systems when fertilizers, herbicides, or other materials are injected into the irrigation system. Assembly must be installed a minimum of 12 inches above the ground. By a state certified backflow assembly tester, requires annual testing thereafter.