Backflow Information

Cross Connection & Backflow Prevention

Walnut Valley Water District is committed to insuring a safe, high-quality, and reliable drinking water system. An important part of WVWD’s water quality program is backflow prevention.

What Is Backflow?

WVWD’s drinking water system is designed to keep water flowing to you. Backflow is water flowing in the opposite direction from its normal flow.


What Is A Cross Connection?

A cross connection is any actual or potential physical connection between a public water system, and any source of non-potable liquid, solid, or gas that could contaminate the drinking water supply.

Devices & Requirements

Backflow Prevention Devices

Backflow prevention devices or backflow preventers are installed to prevent the backflow of contaminants into drinking water through cross-connection. A backflow prevention assembly is an approved, testable assembly that uses check valves and/or relief valves, in different configurations, to prevent potential contaminants from flowing into the drinking water system.  An approved backflow prevention assembly has gone through an approval process at the Foundation for Hydraulic Research and Cross Connection Control at the University of Southern California. This is a two-step process of laboratory tests and a 12-month field test. Only assemblies successfully completing the entire testing procedure are recognized by WVWD as approved backflow prevention assemblies.

Backflow Prevention Device Requirements

Federal and State law requires that water suppliers protect their water systems from contamination. When WVWD makes a determination that the drinking water system may be subject to contamination through a backflow condition, the customer will be notified and required to install an approved backflow prevention assembly.  Per WVWD’s Rules and Regulations, Article 8, the customer has a period of sixty (60) days to complete all corrective action required, including installing and testing a District-approved backflow prevention assembly.

Backflow Prevention Device Testing Requirement

WVWD’s Cross Connection Control Program and the California Department of Health Services require all backflow prevention assemblies to be tested annually.  You will receive a letter as a request to have your annual backflow test completed. Customers must hire a Los Angeles County-certified backflow tester.

You can find a registered backflow testing company here.

Customers must have their test results submitted by the testing company online at  WVWD has contracted Aqua Backflow, Inc. to manage our backflow program. For questions or test results, please email or call 847-742-2296.

To ensure that backflow assemblies are protecting public health and the environment, the State of California’s Administrative Code, Title 17, Chapter 5, Public Health, and Article 8 of our District’s Rules and Regulations [LL1] require the customer of any premises upon which cross-connection (backflow) control devices are installed to maintain the devices in a continuous state of good repair and to have the devices tested annually.

Backflow Theft Prevention

If your backflow prevention device is stolen, you will be without water until the backflow equipment is replaced, inspected, and certified. To prevent theft, WVWD recommends one of the following, an installation guide is available here.

To avoid additional cost and nuisance, the following is recommended:


This activity not only camouflages your device, but the metals are no longer considered clean scrap and are of less value to theft.


Hide a backflow prevention device as part of your landscape. Please ensure access for backflow prevention device maintenance.

Security Equipment

Backflow equipment enclosures, cages, or other security devices are strongly recommended. This reduces the risk of theft and protects devices from being damaged or tampered with. Some plumbing or backflow testing companies are capable of installing security devices.

Security Equipment


Important features include:

• Lock shields that safeguard the unit from bolt cutters,
• Enclosures should be powder coated or made of stainless steel to help prevent corrosion,
• No sharp edges or corners that may cause injury,
• Concrete pad to support and secure enclosure and prevent weeds or grass from growing into the assembly, 
• The area must provide access for testing and service work.

Alternative Security Equipment

The combination of a telescoping arm that attaches to the backflow valve, anchored below grade with a concrete footing, may also help with theft prevention.

Fire Protection System

  • OS & Y Stem protectors to prevent stem theft,
  • By-pass valve locks to prevent water shutoff to remove the device.