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DCVA

Double check valve assemblies may be installed on premises where substances used would be objectionable, but not hazardous to health if they entered the potable water system.

1. Flow characteristics for DCVAs are not standard, so manufacturer's specifications should be consulted for specific performance data. The DCVAs must be sized to provide an adequate supply of water and pressure for the premises being served.
2. Whenever interruption of the water supply is critical, two parallel assemblies should be installed. They should be sized so that either assembly can provide the minimum water requirements and the two together will provide the maximum flow required.
3. Bypass lines on assemblies are prohibited. Pipe fittings which could be used for connecting a bypass line must not be installed.
4. Each assembly must be readily accessible and installed with adequate room for testing and maintenance. DCVAs may be installed below grade, as long as all test cocks are fitted with brass pipe plugs. All vaults should be constructed of suitable materials, well drained, and should be sized to allow for the minimum clearances established below.
   Assemblies 2 inches and smaller should have at least a 3 inch clearance below and on both sides of the assembly. The bottom of the assembly should not be more than 24 inches below grade, if installed in a vault. All assemblies larger than 2 inches should allow a minimum clearance of 12 inches of space on the back side, 24 inches of space on the test cock side, and 12 inches underneath the assembly. In vaults without a fully removable top, a minimum headroom of 6 feet 0 inches is required. An access opening of a minimum of 24 inches square is required on all vault lids.
   Assemblies installed more than 5 feet above floor level must have a platform suitable for use by testing and maintenance personnel.
5. Vertical installations are allowed on sizes up to and including 4 inches, provided they meet the following requirements:
1. The check valves are internally spring loaded.
2. Water flow is upward through assembly.
3. Manufacturer acknowledges a specific assembly can be used in a vertical position.
6. The assembly must be protected from freezing and other severe weather conditions.
7. Prior to installation, all lines should be thoroughly flushed. Installation of a strainer with a removable screen ahead of the assembly is recommended and may be required.
8. All responsibility for leaks and damage is assumed by the property owner. The owner is also responsible for keeping the vault reasonably clean.
9. All DCVA assemblies must be tested immediately upon installation and at least once per year thereafter by an approved certified tester. Having tests performed is the responsibility of the assembly owner. The water District must be informed by the owner whenever any backflow assembly is installed.
10. Variances from these specifications will be evaluated on a case-by-case basis. Any deviations must have prior written approval of the water department.