BeavertonOregon.gov/PublicWorks
Drinking Water Program
Protecting Your Drinking Water (Part I)
Automatic sprinkler systems make watering lawns and gardens easier and save time. But, irrigation water that may be contaminated by weed killers, pesticides or fertilizers can be back siphoned into your drinking water. Irrigation systems not protected by special backflow prevention valves could endanger the health of a household, neighborhood or possibly community. If a cross connection between plumbing containing a harmful substance and a drinking water pipe is not protected the harmful substance may flow back into the water main, and be accidentally consumed by the water customers.
A "cross connection" is a point in a plumbing system where the drinking (potable) water supply is connected directly or can be connected directly to a non-potable source. The Oregon Health Division, a unit of state government, has primary responsibility to regulate public drinking water systems and to enforce the federal Safe Drinking Water Act. The State of Oregon Human Services Department Drinking Water Program administrative rules requires the City of Beaverton to operate our drinking water system free of actual or potential sanitary hazards, including cross connections. Further, the State of Oregon Human Services Department Drinking Water Program requires the City of Beaverton to carry out a local cross connection prevention program.
Examples of cross connections, which could allow harmful substances to be carried into the public water supply, are:
- Chemicals from lawn fertilizing sprayers
- Solar heating systems and swimming pools
- Heating systems using boilers
- Private wells with connection to the public water system
- Fire systems which use black iron pipe or other non-potable piping
Since 1985, the City of Beaverton has required backflow assemblies on commercial and industrial plumbing where cross connection hazards or potential hazards exist. Backflow prevention assemblies have also been required by plumbing codes for residential sprinkler systems, for many years. However, it has been difficult and costly to determine how many residential irrigation systems exist, how many already have backflow assemblies and how many need backflow assemblies to be installed and tested annually.
Residential customers have a lower risk with sprinkler systems than commercial and industrial customers. Nevertheless, Oregon law as well as common sense requires the public water system to be protected from cross connections and potential backflow of harmful substances into our drinking water.
We appreciate your taking the time to read this article and we ask for your cooperation in protecting the City’s water system.
Protecting Your Drinking Water (Part II)
Backflow Prevention-Installation
Weed killers, pesticides, or fertilizers back-siphoned through sprinkler heads or from the ground (saturated by irrigation water) can contaminate water inside irrigation pipes. Without a backflow prevention assembly, a cross connection between plumbing containing a harmful substance and a drinking water pipe could allow backflow of the harmful substance into your household plumbing or a public drinking water distribution main where it could be accidentally consumed by you or other City water users. Protection of residential water systems can be accomplished by using a special backflow prevention valve (assembly or device) to prevent potential risk of contamination to the public supply as required by Oregon law.
A plumbing permit is needed to install a residential irrigation (sprinkler) system whether you, as the property owner, install the sprinkler system or you hire a contractor. The permit ensures that the plumbing codes are followed. Plumbing codes are enforced to ensure the homeowner has a plumbing system that is safe to use for drinking water and to maintain high-quality plumbing systems for you, when purchasing a new or different home or condominium. Obtaining a plumbing permit also ensures that if you hire a contractor, the contractor is licensed and bonded. As a part of the permit process, the City’s plumbing inspector and cross-connection inspector will inspect the new system to verify that an approved backflow assembly is properly installed. The City’s inspectors will also verify the location, serial number, and testing of the backflow assembly.
There are four approved types of backflow assemblies. Each of these assembly types have specific installation requirements. View a picture of the four backflow assembly installations.
The plumbing code requires all water service yard piping to be buried at least 18″ to 24″ in depth to protect against freezing. If you choose an Atmospheric Vacuum Breaker (AVB) note that it does not require testing but it must be inspected. The City will inspect AVBs annually at no cost to the homeowner, to ensure they are operating properly.
Under Oregon Administrative Rules (OARS), all other types of backflow assemblies require annual testing by a certified testing company to be paid for by the homeowner. The test is to ensure that the assembly is operating correctly. See list of certified testers.
Since 1985, the City of Beaverton has required backflow assemblies on commercial and industrial plumbing where cross connection or potential hazards exist. Backflow prevention assemblies have also been required for residential irrigation systems for many years. However, since many irrigation systems have been installed without permits or backflow assemblies, it has been difficult and costly to determine how many residential irrigation systems exist, how many have backflow assemblies, and how many need backflow assemblies to be installed and tested annually.
To help answer these questions, the City of Beaverton has been conducting a survey of residential properties. Historical plumbing permit records are being reviewed to verify that City backflow assembly records match old plumbing permits, which include previously installed assemblies.
Staff is comparing field visual survey results with City backflow records. Early indications from the survey indicate that from 45 to 50 percent of homes will require either installation of backflow assemblies or testing of assemblies that have not had them in the past. When the survey is complete staff will recommend a program to the City Council to bring all residential irrigation systems into compliance with State and City regulations.
For assistance with the type of backflow assembly best for your irrigation system, contact your local water provider. Within the Beaverton city limits, there are four separate public water providers - see Water Service Areas below.
For assistance or advice in choosing a backflow assembly or if you are not sure which water provider serves you, please contact the Cross Connection Control Inspector of the Engineering Division at (503) 350-4042 or email: jmitchell@ci.beaverton.or.us.
Water Service Areas
- The City of Beaverton provides water to approximately 80 percent of the population living within the City limits.
- Northeast Beaverton is served by West Slope Water District (503) 292-2777.
- East near the County line is served by either Raleigh Water District (503) 292-4894 or Tualatin Valley Water District (503) 642-1511.
- Northwest Beaverton is served by Tualatin Valley Water District (503) 642-1511.
Backflow Assembly Testing
All assemblies must go through rigid and extensive factory testing through the Foundation for Cross Connection Control and Hydraulic Research (FCCCHR) at the University of Southern California before it is considered to be an approved assembly. All assemblies must be pressure tested according to their designed operating pressure for use on cold-water service. The hydrostatic test pressure is twice the maximum rated working pressure of the assembly. The entire assembly is subjected to the hydrostatic test, both in the normal direction of flow and in the reverse direction of flow with the opposite side of the barrier open to the atmosphere. There must be no leakage across any barrier, and the hydrostatic test pressure is maintained for a minimum of ten minutes for each test.
When your assembly has the required annual test, a tester attaches a test gauge to ensure the check valves hold to the proper value.
Training of Testers
The OARS, Chapter 333, Section 61-0072 states, "A person shall not perform tests on backflow prevention assemblies unless they are certified as a backflow assembly tester by the State of Oregon Human Services Department Drinking Water Program." Each tester must successfully complete the training and hands on testing before receiving a certification. They must re-certify every two years. The testers are required to have the test gauges calibrated annually. Once a test is performed on an assembly, the tester will complete the appropriate paperwork for that test. Copies of the test report will be given to the water purveyor and customer; the tester will retain one for his own records. Tests performed by certified testers shall be in conformance with procedures established by the FCCCHR.
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