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1. What is a cross-connection?

It is any connection between your drinking water and an unapproved source of water or any other contaminant. With a cross-connection, your drinking water can become contaminated when a backflow condition occurs.

So, what is backflow? Backflow is when the water in your pipes (the pipes after the water meter) goes backward (the opposite direction from its normal flow). There are two situations that can cause the water to go backward (backflow):

• Backpressure - the pressure in your pipes is greater than the pressure coming in
• Backsiphonage - a negative pressure in one of the pipes.

2. I received a letter from the City notifying me my backflow assembly needs to be tested. Is there a list of certified testers?

For our residents' convenience, the City maintains a list of Certified Backflow Testers (PDF) (updated April 2023).

If you experience problems with any of the testers on the list please notify the City's Cross Connection Specialists at 509-967-5434 or by email.

3. What is considered a potential hazard?

Any possibility of pollutants, contaminants, and system or plumbing hazards is considered a potential hazard. Examples may include:

• Underground sprinklers utilizing potable water
• Water softener
• Swimming pool, etc. 

Putting the garden hose in a swimming pool to fill it; putting a garden hose in a pet's water bucket or fish tank can unwittingly create a cross-connection.

So you may ask …What's the big deal? The big deal is backflows due to cross-connections can cause sickness and death.

4. I want to connect my underground irrigation system to the City potable water in addition to the CID or the KID, what is the proper way to connect to both systems?

To connect to both Columbia Irrigation District (CID), Kennewick Irrigation District (KID), and the City's potable water system you will need to install a Reduced Pressure Backflow Assembly (RPBA). You will need to have your RPBA inspected by the City Cross Connection Specialist and tested by a certified backflow tester once you have installed your assembly. You are also required to have your RPBA tested annually by a certified backflow tester.

Another option: If your irrigation service is interrupted use your garden hoses connected to your home's exterior faucets. This option does not require you to install an RPBA and have the RPBA annually tested.

Please note you can not connect garden hoses from your home's exterior faucets to your underground sprinkler system.

5. I am installing an underground sprinkler system utilizing only City potable water. How do I properly connect my underground sprinkler system to the City's potable water?

First, obtain an Underground Sprinkler Installation Permit from our Cross Connection Specialist.

You will need to properly install a backflow assembly approved by the Department of Health. Below you will find several installation diagrams. Each backflow assembly has specific installation requirements which may not work in all situations. Contact the City's Cross Connection Specialist, 509-967-5434, for assistance.

Additional Resources

• Double Check Valve Assembly (DCVA) Installation (PDF)
• Pressure Vacuum Backflow Assembly (PVBA) Installation (PDF)
• Atmospheric Vacuum Breaker (AVB) Installation (PDF)

Once your device has been installed do not backfill. You will need to contact the City's Cross Connection Specialist, 509-967-5434, to have it inspected.

You are required to have your backflow assembly tested annually. The City will send a reminder letter 30 days prior to your annual test due date. Please contact one of the Certified Backflow Testers to have your test completed.

6. I am going to disconnect my underground sprinkler system from the City potable water system. How do I properly disconnect from the City's potable water system?

The following diagram will aid you in disconnecting and removing your backflow assembly from the City potable water system. Do not backfill once you have removed your backflow assembly. Prior to connecting your underground sprinkler system to KID or CID, you will need to contact the City's Cross Connection Specialist once you have completely disconnected from the system, to have the disconnection verified.

• Double Check Valve Assembly (DCVA) Removal (PDF)

7. What happens if I do not have my backflow device tested?

Read through the Civil Penalties For Cross-Connection - P03-11 (PDF) - updated March 2018.