Cross Connection and Backflow Prevention

• What is a cross connection?
• What is backflow?
• How can cross connections and backflow affect my drinking water?
• What can I do to prevent backflow?

• A garden hose is submerged in a bucket of soapy water, hot tub, or swimming pool.
• A lawn irrigation system is connected directly to the drinking water system.

• Backsiphonage - The pressure in the drinking water system is lowered. This type of backflow can result from water line flushing, fire fighting, or water main breaks.
• Backpressure - The pressure in a customer's piping system is greater than that of the drinking water system. This primarily occurs in commercial applications involving pumps, high rise buildings, or boilers.

• A garden hose is submerged in a bucket of soapy water. A water main breaks down the street, lowers water pressure, and soapy water from the bucket is backsiphoned through the hose and into the water system (backflow). At the same time, someone at the residence pours a glass of water from the kitchen faucet. The soapy water flows back out the kitchen faucet, creating a contaminated glass of water.
• A sprinkler head from a lawn irrigation system sits in a puddle of water containing fertilizer (cross connection). Two blocks down the street, firefighters connect to the water system to fight a fire and water pressure is lowered. The puddle of water containing fertilizer is backsiphoned through the sprinkler head and into the water system (backflow.) Meanwhile a neighbor is taking a shower. The fertilizer-contaminated water flows back through the water system and out the neighbor's shower head.

• Avoid creating a cross connection when filling a bucket, hot tub or swimming pool.  By installing a ‘hose bib vacuum breaker’ on any faucet used for connecting a hose and a gap between the hose and the water in the container, you eliminate the cross connection and the possibility of backflow.
• Install a backflow prevention device between the lawn irrigation system and the drinking water system to prevent backflow.

• What is a backflow prevention assembly?
• When is a backflow prevention assembly required?
• What are the different types of backflow prevention assemblies, devices, and methods?

• Lawn irrigation system
• Fire Sprinkler System
• Water feature such as an ornamental fountain or fish pond
• Swimming pool, spa, or hot tub
• Solar heating system
• Well

• Do I need a permit to have a backflow prevention assembly installed and is there a permit fee?
• Who can install a backflow prevention assembly?
• What does it cost to install a backflow prevention assembly?

• Why am I required to have my backflow prevention assembly tested?
• How often do backflow assemblies need to be tested?
• Who is responsible for the testing and maintenance of the backflow assembly?
• What is a Certified Backflow Assembly Tester and how can I find one?
• What does it cost to test a backflow prevention assembly?
• What happens if I do not have my backflow prevention assembly tested and maintained as required?

Why am I required to have my backflow prevention assembly tested?
Backflow prevention assemblies have internal seals, springs, and moving parts that wear out. Regular testing is required to ensure backflow prevention assemblies are functioning properly and have not been bypassed. A visual check of air gap assemblies is sufficient, while mechanical assemblies must be tested with special equipment.

How often do backflow assemblies need to be tested?
State rules requires that all backflow prevention assemblies must be tested at least annually and immediately following any repair, maintenance, or relocation. Assemblies that repeatedly fail may require more frequent testing or replacement.

Who is responsible for the testing and maintenance of the backflow prevention assembly?
It is the responsibility of the property owner to ensure the assembly is in good operating condition. A person who is state-certified in backflow assembly testing must perform the test and submit the results to the City of Tigard. If any repair work or maintenance is performed, the assembly must be retested immediately. All test results must be submitted to the City of Tigard within 10 days.

The Certified Tester should mail original test results to the City at:
City of Tigard
Water Division - Cross Connection Program
13125 SW Hall Blvd.
Tigard, OR 97223

What is a Certified Backflow Assembly Tester and how can I find one?
A Certified Backflow Assembly Tester is someone who has completed a state-approved, 40-hour training course in backflow prevention assembly testing and has passed a proficiency test to prove his/her knowledge. Many plumbing, fire sprinkler, and lawn irrigation companies, as well as backflow prevention testing companies, are listed in local telephone directories and provide testing services in the Tigard area. As a convenience, the City of Tigard maintains a partial list of companies offering the services of Certified Backflow Assembly Testers.

What does it cost to test a backflow prevention assembly?
Backflow prevention assembly testing is done by private companies who set their own rates. Testing costs vary, so getting quotes from several companies is recommended.

What happens if I do not have my backflow prevention assembly tested and maintained as required?
Oregon Administrative Rules (OAR) Chapter 333-61-070 mandate the City of Tigard establish and maintain a cross connection control program. The OARs and the Tigard Municipal Code, Chapter 12.10.110, require the city to terminate water service should a property owner fail to comply with cross connection regulations. This includes testing and maintenance of backflow prevention assemblies.           

For more information regarding cross connection and backflow, please contact hung@tigard-or.gov, Cross Connection Specialist or phone 503-718-2603.