Cross Connection Information
The most common way contaminants enter the drinking water system are through "cross-connections" in your home plumbing system. A cross-connection is an actual or potential link between your home plumbing and a non-potable water source such as a sink full of dirty water or a hose-end sprayer full of poison.
Backflow is just what it sounds like: water flowing backward in an unintended direction. Backflow from a cross connection can occur when pressure in the water main drops below the line pressure in your home causing back siphonage. This effect can suck water back through a hose or pipe from wash basins, ponds, boilers, lawn sprinklers, swimming pools, hot tubs, etc., into your home's plumbing or even back into the Public Water System.
Inexpensive Hose Bibb Vacuum Breakers (available at most hardware stores) installed on each of your threaded faucets could prevent you from drinking what the end of a hose has been left in.
What You Can Do To Protect Your Drinking Water From Contamination
In accordance with WAC 246-290-490, and the Rainier View Water Company, Inc. Conditions of Service, Backflow Prevention Assemblies must be installed and tested annually if any of the following apply to your property:
Please arrange to have your existing Backflow Prevention Assemblies tested immediately and then annually thereafter. If you have had a test done within the last calendar year, please send in the Backflow Assembly Test Report. If you do not have a copy of this report, have the Backflow Assembly Tester forward a copy of this report to this office.
- If you have an underground irrigation system or sprinklers, please test the Double Check Valve. It should be where the irrigation system tees off of the main water line to your house. If you do not have a Double Check Valve Assembly, one must be installed and tested. If your irrigation system has injection ports for lawn chemicals, this backflow preventer must be upgraded to a Reduced Pressure-Principle Backflow Assembly installed above grade in an insulated enclosure.
- If you have a swimming pool or a hot tub that is not filled with a hose, but fills through an outlet that is below water, please test the Reduced Pressure-Principle Backflow Assembly. If you do not have one, please install one at the point of use so that it isolates the pool/tub from your potable water line. If your pool/tub fills with a hard plumbed air gap (like a kitchen spigot, above water level) a backflow preventer will not be necessary.
- If you have a well on your property that is in use and connected to your home plumbing, please install and test a Reduced Pressure-Principle Backflow Assembly at the water meter for the purpose of premises isolation. If the well is not interconnected to the home plumbing, please install and test a Double Check Valve Assembly at the meter for the purpose of premises isolation. If the well has been properly decommissioned, please send proof of this and no backflow prevention assembly will be necessary.
- If you have a Home Dialysis Machine, a Reduced Pressure-Principle Backflow Assembly must be installed at the point of use to isolate your potable water lines from the appliance.
- Any heat exchangers, solar heaters or boilers must have a Reduced Pressure-Principle Backflow installed on the water make up line to isolate the appliance from the potable water lines of your home.
- Please insure that if your water treatment system/water softener has a drain hose for a backwash/cleaning cycle that the hose is properly air gapped (not put down inside the drain so as to contact sewage).
- If you have a boat dock with potable water available, please install and test a Reduced Pressure-Principle Backflow Assembly at the point of use to isolate the dock from your potable water supply.
- If you have any other water using devices that you think might pose a cross connection threat to your public water supply, do not hesitate to contact us to learn how to protect your drinking water.
If you have any questions, or would like to declare that none of the above listed conditions exist at your property, please contact our main office via one of the following methods:
Phone: (253) 537-6637
Cross Connection Information
Double Check Valve Information
Reduced Pressure Backflow Assembly Information
Backflow Test Form
Residential Water Use Questionnaire
Commercial Water Use Questionnaire
Backflow Assembly Testers
*A PDF viewer for the above forms is available from Adobe® by clicking here