Annual Backflow Notice

Annual backflow notices will be mailed beginning Thursday, April 9, 2026. The information below provides an overview of the Backflow Program.

 2026 Backflow Assembly Testers List

What is this notice for?
This courtesy notice is to inform you that your Backflow Prevention Assembly is due for its required annual test.

Do I need to keep this notice card?
Yes. Please retain the notice card, as it will assist your certified tester in completing and submitting the required report. The work order number provided is necessary for online submission.

Why am I receiving this notice? 
You are listed as the owner of a Backflow Prevention Assembly. Backflows prevent contamination of public drinking water, because of this, Washington State and the EPA legally require annual testing.

How do I test my backflow assembly?
The Water Division maintains a list of certified backflow testers available for contact. Once a test has been scheduled, the selected tester will conduct the backflow test and submit the results directly to the Water Division.

If you have any further questions, you can reach our Regulatory Compliance office at 
509-527-4370 or email cccp@wallawallawa.gov

Cross Connection Control Program

State drinking water rules require public water systems to develop and implement Cross Connection Control (CCC) programs in order to protect our water system from potential contamination. As part of a CCC program, backflow prevention assemblies must:

Be installed on irrigation systems that are connected to the City's water system. This assembly helps prevent "backflow," which could carry contaminants into the public water system.

Must get tested (when installed and annually after that) to make sure they work properly.

A Department of Health certified backflow assembly tester must perform and certify testing.

Backflow prevention is required in accordance with WAC 246-290-490 Cross Connection Control.

What is Backflow?

Backflow occurs when water or other substances flow in the opposite direction than intended, allowing contaminants to enter the public water system or consumer's plumbing. A backflow incident occurs when biological, chemical, or physical contaminants enter the drinking water supply (under backflow conditions) via unprotected cross‐connections. A cross connection is any actual or potential physical connection between a drinking water system and any other non‐potable substance (liquid, solid, or gas). Cross connections can occur at many points throughout a community's water system. Some specific examples of backflow incidents that can occur are:

• Lawn chemicals backflowing (siphoning) through a garden hose into indoor plumbing and potentially into the distribution system.
• Carbonated water from a restaurant's soda dispenser entering the water system due to backpressure.
• Backflow of chemicals from industrial buildings into the distribution system mains.

Water from the customer's system can backflow into the water main when the pressure in the City's water main is lower than the pressure in the customer's system. This can occur when there is a break in the water main or during construction or firefighting activities.