Swan Island Dahlia Farm at Dahlia Festival

Two Steps for Clean Water

Backflow Prevention Apparatus
If you have an underground irrigation system, be sure the proper backflow prevention apparatus is installed.
Irrigation system Atmospheric Vacuum Breaker

Depending on the design of your irrigation system, the apparatus type and location(s) can vary widely. Typically a newer system may have a Double Check Valve Assembly (DCVA). These may be installed below grade, have control valves beyond the assembly, and can be installed at the low point of your system, if that is the best location for it. Other devices or assemblies that may be adequate for certain layouts include Atmospheric Vacuum Breakers (AVB), Pressure Vacuum Breakers (PVB), and Spill-Resistant Vacuum Breakers (SVB). If your irrigation system dispenses chemicals, a Reduced Pressure Principle Valve Assembly (RPVA) is the required apparatus.

To prevent possible damage to your plumbing due to the thermal expansion of water trapped beyond RPVA’s—and also DCVAs if similarly placed in the water line between your home and water meter—a Thermal Expansion Device is typically attached to your hot water tank.

Atmospheric Vacuum Breaker

Garden hoses can create a risk of backflow contamination. Do not leave garden hoses submerged in a swimming pool, pond, laundry sink, or car wash bucket.

Be sure you have an atmospheric vacuum breaker (AVB) installed on each of your hose bibs. Find them at your local hardware store. Simply screw them on to install.

View the Backflow Prevention Assembly Installation and Operation Standards (PDF).

Test Annually
Test backflow prevention assemblies annually

Regular testing will ensure that DCVAs on irrigation systems continue to function properly, and help you identify any maintenance issues. Many landscaping companies perform backflow testing. Contact Canby Utility or view the list below for backflow testing companies. We will help you remember to have your backflow devices checked annually by sending you reminders throughout the year.