BackflowState regulations require that residential, commercial and industrial customers served by a public water system take adequate measures to protect the public water system from potential contamination. Under certain conditions, water from private plumbing can flow into the public water distribution system. This is referred to as backflow. Here’s what you need to know.

What is backflow?

Backflow is the reverse flow of water or other substances into the treated drinking water distribution system. There are two types of backflow: (1) backpressure and (2) backsiphonage.

Backpressure happens when the pressure of the contaminant source exceeds the positive pressure in the water distribution main. An example would be when a drinking water supply main has a connection to a hot water boiler system that is not protected by an approved and functioning backflow preventer. If pressure in the boiler system increases to where it exceeds the pressure in the water distribution system, backflow from the boiler to the drinking water supply system may occur.

Backsiphonage is caused by a negative pressure (vacuum or partial vacuum) in the water distribution system. This situation is similar in effect to the sipping of water through a straw. In the drinking water distribution system, negative pressure (backsiphonage) occurs during a water main break or when a hydrant is used for firefighting.

What is cross-connection?

Cross-connection is any actual or physical connection between a potable (drinkable) water supply and any source of non-potable liquid, solid or gas that could contaminate drinking water under certain circumstances.

Why should you be concerned?

Backflow may affect the quality of the drinking water at your home or business and has the potential to create health hazards if contaminated water enters your water supply plumbing system and is used for drinking, cooking or bathing.

Unprotected cross-connections with water supply plumbing or public drinking water piping systems are prohibited.

Who is responsible?

We are all responsible for protecting our water supply from backflow that may contaminate our drinking water. This includes complying with the plumbing code and avoiding unprotected cross-connections.

State and local plumbing inspectors typically have authority over plumbing systems within buildings while state regulatory agencies and public water suppliers regulate protection of the distribution system at each service connection.

Water customers have the ultimate responsibility for properly maintaining their plumbing systems. It is their responsibility to ensure there are no unprotected cross-connections and that any required backflow prevention devices are tested in accordance with state requirements and maintained in an operable condition.

Am I in compliance?

We will help determine whether your residence or business is in compliance with the cross-connection/backflow prevention regulations. Preprinted backflow test report forms—containing the make, model, size, serial number and site location—can be obtained for any existing backflow by contacting the Water Quality Specialist.

Otherwise, the tester may submit results for any backflow assembly test by using the Backflow Maintenance Report.

Mail the original completed test report form to:

City of Santa Ana Water Resources Division
Engineering Department
220 S. Daisy Avenue
Santa Ana, CA 92703
Attention: Water Quality Specialist

Tests must be performed by a backflow prevention device tester certified by the Orange County Health Care Agency and has a valid City of Santa Ana Business License.

How can I prevent backflow?

  • Be aware of cross-connections, eliminate or isolate them.
  • Maintain air gaps on sinks and when using hoses.
  • Do not submerge hoses or place them where they could become submerged.
  • Use hose bib vacuum breakers on fixtures (hose connections in the basement, laundry room, and on outside faucets/spigots).
  • Install approved backflow prevention devices on lawn irrigation systems and on fire sprinkler system services. Type of required backflow prevention devices will be determined based on the potential type of pollutants or contaminants; high, low or moderate.