Backflow assemblies are required by law to be tested at least once a year to make sure they are functioning properly. The tests conducted on the assembly are done by independent contractors certified by the state; they are not done by Portland Water Bureau employees. The Portland Water Bureau does maintain records on which sites have assemblies installed and mail notifications for annual testing . The Portland Water Bureau also sends an annual report to the Department of Human Resources regarding the testing of all required backflow assemblies.
Protecting Backflow Assemblies from Freezing.
To protect above-ground backflow assemblies from freezing, recommendations include:
Install an insulated enclosure and or provide electric heat tape.
On irrigation systems, make sure a low point drain has been installed, shut off water supply and open all test cocks and shut-off valves on the backflow assembly half-way and leave open.