County of Los Angeles Waterworks Districts

Cross-Connection Control and Backflow Prevention

A cross-connection is any connection between the Waterworks Districts' safe drinking water system and any other untested water source, system, or equipment that may contain unsafe substance. The Districts' public water systems are designed to keep water flowing in one direction--from the Districts' water main to the customers' connections. When an undesirable condition known as backflow occurs, water is allowed to flow in the opposite direction and may bring contaminants or pollutant into the public drinking water supply through a cross-connection. Backflow is caused by a backsiphonage or a backpressure condition in the public water system. Backsiphonage may occur when the pressure in the public water system drops below atmospheric pressure and creates a vacuum that may pull unsafe substance into the public water supply. Backpressure may occur when the pressure from a private water system becomes greater than the pressure in the public water system. This difference in pressure may allow unsafe substance from the private water system to enter the public water system. Approved backflow prevention assemblies are designed to prevent backflow of contaminants or pollutants from entering the public water systems.
Waterworks Districts' Cross-Connection Control and Backflow Prevention Program
In order to protect our public water systems from potential contamination, the Waterworks Districts have implemented a Cross-Connection Control and Backflow Prevention Program (Program) in accordance with the California Administrative Code, Title 17. The Program consists of the following elements: Maintain inventory of all the backflow prevention assemblies for the Districts' water systems Ensure annual testing of all backflow prevention assemblies Complete plan reviews for new connections to the Districts' water systems Train employees on cross-connection control and backflow prevention As a water supplier, the Waterworks Districts are required by federal and state laws to protect the public water system from contamination. When backflow protection is necessary for connections to the Districts' public water system, the customer will be required to install approved backflow prevention assemblies and to have them tested by a certified tester. After installation and initial testing, the assemblies are required to be retested on an annual basis by a certified tester. The Districts will notify each affected customer when it is time for the annual test of their backflow prevention assemblies. The written notice includes a Backflow Prevention Assembly Field Test and Maintenance Report Form and a web link to a list of employers of certified testers. Water shut-off notices will be issued to customers who fail to arrange for testing of their backflow prevention assemblies by a specified due date. If the customer is non-responsive within the allotted time, the Districts may terminate water service to the property until the assemblies are tested and the completed form is submitted. For more information on the Districts' Cross-Connection Control and Backflow Prevention Program, please contact Mr. David Young at (626)300-4680 or dyoung@dpw.lacounty.gov.
Resources
Backflow Prevention Assembly Field Test and Maintenance Report Form Approved Backflow Prevention Assemblies LACWD accept backflow prevention assemblies approved by the USC Foundation for Cross-Connection Control and Hydraulic Research. Backflow prevention assemblies for domestic lines must also meet the "lead free" requirements per Health and Safety Code (HSC) section 116875. Please contact Mr. David Young at (626) 300-4680 or dyoung@dpw.lacounty.gov to request partial copies of the list of approved backflow prevention assemblies for specific sizes and types. Employers of Certified Backflow Prevention Assembly Testers A list of employers of certified testers is available on the Los Angeles County Department of Public Health's website: http://www.publichealth.lacounty.gov/eh/docs/ep_cross_con_emplist.pdf