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Public Utilities

Cross-Connection Control and Backflow Prevention

The City of San Diego Public Utilities Department spends millions of dollars each year to ensure the safety of our drinking water. A vital part of this effort is the department's Cross-Connection Control and Backflow Prevention Program.

Water distribution systems are designed so that water flows in one direction from the treatment plant to the customer.

Cross-connections are any unprotected actual or potential connection or structural arrangement between a consumer's potable water system and any other source or system through which it is possible to introduce used water or substances other than the intended potable water. Bypass arrangements, jumper connections or any other temporary or permanent connections through which backflow can occur are considered to be cross-connections. Backflow is the reversal of the flow of water or mixtures of water and other liquids or substances into the distribution pipes of the water supply from any source or sources.

Federal and state laws require water purveyors to protect their systems from cross-connections and backflow. The City works closely with consumers, architects, contractors and engineers to ensure compliance with cross-connection control and/or backflow prevention requirements. If you have been contacted by the Public Utilities Department and need a backflow prevention assembly installed or tested, see the City of San Diego Approved List of Backflow Testers.

All backflow devices are required to have annual testing.

For questions regarding device requirements and approvals for meter protection and fire protection, or for more information about this program, contact us at 858-292-6329 or via email at

If you are a backflow tester currently certified with the American Water Works Association (CA-NV) or the American Backflow Prevention Association (regional) and are interested in testing backflow assemblies within our district, please email to schedule an appointment for the Tester Orientation. The orientations are held in January and July of each year. You will be required to provide current copies of gauge calibration and backflow tester certifications, issued by either of the previously mentioned associations.