Alert Emergency Alert

Coronavirus Updates Provided by the City of Tigard

Read More
JOBS  |  MAPS  |  Codes  |  CONNECT  |  FORMS  |  CONTACT
  • Backflow Cross Connection
  • Backflow-Prevention-Device-Chart

Public Works - Water

Cross Connection and Backflow Prevention

We sincerely thank all our water customers that completed the annual irrigation backflow assembly testing in 2020. Your help is essential in protecting our drinking water supply system from health contaminants.

Backflow Testing
If you are a property owner with an in ground sprinkler system, a fire suppression system, or a private well state and local laws require that you install and maintain a backflow prevention device on your service line and have it inspected yearly by a certified tester.

Did You Know...
The government of the United States, through the Environmental Protection Agency (EPA), mandates that all supplier of drinking water provide and maintain clean, safe drinking water. One of the most effective tools available to the water purveyor to accomplish this goal is a cross connection control program.

Water users may be surprised to learn they play an essential role in maintaining safe, clean drinking water. By preventing pollutants and contaminants from entering the drinking water system, water users help to protect the quality of the water for themselves and their community.

The Basics

What is a cross connection?
Cross connection refers to an actual or physical connection between the drinking water system and any pipe, vessel, or machine containing a non-potable fluid, contaminants, such as chemicals, bacteria, pesticides, or waste water.

  • 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.
What is backflow?
Backflow occurs when water flow is reversed from its intended direction and, by way of a cross connection, is pushed or siphoned back into the drinking water system. Backflow can occur by the following mechanisms:

  • 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.
How can cross connections and backflow affect my drinking water?
If a cross connection exists and backflow occurs, contaminants can be drawn back through pipes and into the drinking water system. This has the potential to pollute drinking water and create a potential health hazard.

  • 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.
What can I do to prevent backflow?
The easiest way to avoid backflow is to eliminate cross connections between the drinking water system and contaminants. Sometimes cross connections cannot be avoided. In these cases, the installation of a backflow prevention device will stop backflow.

  • 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.

Backflow Prevention Assemblies

What is a backflow prevention assembly?
A backflow prevention assembly is a mechanical valve arrangement, which prevents the reversal of water flow, once it has passed through the valve. There are different types of backflow prevention assemblies for different situations and different degrees of hazard. (See OAR 333-61-0071 for Backflow Prevention Assembly Installation and Operation Standards) 

When is a backflow prevention assembly required?
Anytime a connection to the water system is made, the City's Permit Center should be contacted to determine backflow prevention requirements. The Permit Center is located at 13125 SW Hall Blvd. in Tigard and can be reached at 503-718-2439. 

A backflow prevention assembly may be required if you have a:
  • 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
City code prohibits any type of cross connection which could endanger the water system. Cross connections are regulated by both the Oregon Health Authority and the City of Tigard. 

What are the different types of backflow prevention assemblies, devices, and methods?
Click here for information on types of backflow prevention assemblies, devices, and methods


Do I need a permit to have a backflow prevention assembly installed and is there a permit fee?
Yes, a plumbing permit is required to install a backflow prevention assembly. Permits can be obtained through the City's Permit Center, 13125 SW Hall Blvd.,Tigard. For permit fee information, contact the Building Permit Technicians at 503-718-2439. 

Who can install a backflow prevention assembly?
The property owner, a licensed plumber, or a landscape contractor licensed to install backflow prevention devices. A plumbing permit is required.

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


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, Cross Connection Specialist or phone 503-718-2603.

What if I choose not to use my current in-ground irrigation system?
Property owners may choose to discontinue using their lawn irrigation system for a variety of reasons, but backflow prevention requirements are still in effect and enforced unless the system is permanently disconnected.

To permanently disconnect your system:

  • It is recommended that you consult with and/or hire a licensed plumber or professional irrigation company.
  • Determine if you have outdoor garden hose spigots that are tied to the lawn irrigation system. This will be important to know where to cap the system.
  • Contact the City of Tigard Cross Connection Control Program at 503-718-2603 for more information.

Please note:

  • A building permit is not required to remove a backflow prevention device and/or to disconnect a lawn irrigation system.
  • A shut-off valve is not a sufficient method for backflow prevention.

Contact the City of Tigard Cross Connection Control Program at 503-718-2603 for more information.

Meet Hung Nguyen, Cross Connection Specialist

Protecting Our WaterHung Nguyen, Cross Connection Specialist
Meet Hung Nguyen. As the city’s Cross Connection Specialist, he spends his time ensuring that water delivered to city customers is safe to drink.

For Hung, this has become part of his life’s work. He’s worked for the City of Tigard for 31 years, and in the water division since 2000. “I come from Vietnam and have experienced firsthand the effects of poor water quality,” he tells me. “Back home the water was not suitable for drinking—from rivers and wells—but we had no choice. “What is most meaningful about my job is protecting people from health hazards. Kids, elders, that is why I do what I do—and why I continue to bug everyone.”

Water systems depend on water pressure to keep water flowing in the intended direction through the pipes. Anything that causes a change in water pressure (like water main breaks, firefighting, etc.) can create a reverse flow, from the customer’s plumbing system back into the public water system. This is called backflow.

“Backflow protection prevents the mixing of irrigation water, for example, with our drinking water,” says Hung. “This is important because that irrigation water may have been exposed to fertilizers and other outdoor chemicals that can be harmful.” Additional cross connections where backflow devices may be installed include fire sprinkler systems, boilers used for heating, and more.

All Tigard Water Service Area customers are required to have their backflow prevention devices tested each year by June 1. Hung receives, tracks and reports on the tests from residential and commercial property owners. All told, about 6,000 residential customers and 500 commercial customers in the Tigard Water Service Area have a backflow prevention device that requires annual testing. Last year, 77% of residential customers completed the required test.

“We cannot survive without water,” Hung reminds us. “There was a time in my life when water was divided up by the teaspoonful.”

“Everyone has the same water source so we need to work together. It is not the city’s water—it’s our water.”
Hung Nguyen
Cross Connection Specialist 

For More Information
»  Download our Informational Brochure
»  View the Oregon Health Authority website

Request email notification when page changes Email Me