Water Authority Cross Connection Control Program

The mission and purpose of the Cross Connection Control Office is to enforce cross connection control by containment under the provisions of the Water Authority Cross Connection Control Ordinance.  The Cross Connection Control Staff is the designated Enforcement Authority to enforce the Ordinance requirements.

To protect the public water system, any water customer that uses hazardous materials is required to install backflow prevention devices at the service connection.  In addition, all non-residential irrigation systems must have a pressure vacuum breaker, spill-resistant pressure vacuum breaker or a reduced pressure principle backflow prevention assembly at the service connection on the public water system.  Such devices shall be approved by the Water Authority.

What is a Cross-Connection?

Cross connections are present when potable water connected to the public water supply is used for (but not limited to) fire protection, irrigation, heating and cooling systems, manufacturing and medical. 

A cross connection is any actual or potential physical connection between a potable water line and any pipe, vessel or machine containing a non potable liquid, or has the possibility of containing a non potable liquid, solid or gas, such that it is possible for the non potable liquid, solid or gas to enter the potable water system by backpressure or backsiphonage (backflow).  To prevent contamination of the public water system all cross connections must be identified, documented, placed under control and monitored on a yearly basis.

What is a Backflow?

Water normally flows from a high water pressure to a lower water pressure.

Backflow is the undesirable reversal of water flow.  Contaminated water from cross-connected plumbing within a customer’s water system can backflow into the public water system.  Backflow may be caused by a backpressure or backsiphonage condition.

Backpressure occurs when water is forced or pushed backwards because the customer’s water system pressure exceeds the operating pressure of the public water system.  Examples of conditions that can contribute to an increase in water pressure include: circulating pumps, booster pumps, injection pumps, boilers, and pressure vessels and elevated piping systems.

Backsiphonage occurs when water from the customer’s water system is drawn backward as a result of negative or decreased pressure in the water supply system.  A backsiphonage condition could be caused by a waterline break or by flowing a fire hydrant in the public water system.

Backflow Prevention

Approved methods and types of backflow prevention assemblies and devices include:

1. Air Gap (AG).
2. Reduced Pressure Principle Backflow Prevention Assembly (RP).
3. Pressure Vacuum Breaker Backflow Prevention Assembly (PVB).
4. Spill-Resistant Vacuum Breaker Backflow Prevention Assembly (SVB).
5. Double Check Valve Backflow Prevention Assembly (DC). DCs are approved for use only on limited installations and approved by the Cross-Connection Engineer.
6. Atmospheric Vacuum Breaker (AVB) Device.

A Certified Backflow Prevention Device Tester must inspect and test backflow prevention assemblies in accordance with approved methods and procedures and complete and submit accurate and timely reports (download a copy of the Backflow Prevention Assembly Test Report) to the Cross Connection Control Office. The tester must report any discovered discrepancies associated with an existing backflow prevention assembly or device or existing cross-connections within the customer's water system to the customer and to the Cross Connection Control Office.

For more information call the Cross Connection Office at 857-8210 or e-mail This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .