Cross Connection Control Information

The Columbia Valley Water District staff is committed to providing quality, cost-efficient service in the production, treatment, testing and delivery of safe drinking water to all residential and commercial users.


Safe and reliable drinking water is a carefully manufactured product.  In order to help ensure safe drinking water the Columbia Valley Water District has adopted a Cross Connection Control Program.  This Program is a part of our effort to ensure safe and reliable drinking water and is required under WA State Department of Health.  

What is a Cross Connection?

A cross-connection is a direct or potential connection between any part of the public water supply system and a source of contamination or pollution. The most common form of cross-connection is a garden hose, which is easily connected to the public water supply system and can be used to apply a variety of potentially dangerous substances, including chemicals and fertilizer. Other common cross-connections include dishwashers, toilets, pressure washers, boilers, pools, and lawn sprinkler systems.

How Does Contamination Occur 

Water normally flows in one direction, from the public water system through the customer's cold or hot water plumbing to a sink connection or other plumbing fixture. The plumbing fixture is the end of the potable water system and the start of the waste disposal system. Under certain conditions water can flow in the reverse direction.  This is known as backflow. Backflow occurs when a backsiphonage or backpressure condition is created in a water line.

Backsiphonage may occur due to a loss of pressure in the water distribution system during a high withdrawal of water for fire protection, a water main or plumbing system break, or a shutdown of water main or plumbing system for repair. A reduction of pressure below atmospheric pressure creates a vacuum in the piping. If a hose bibb was open and the hose was submerged in a wading pool during these conditions, the non-potable water in the pool would be siphoned into the house’s plumbing and back into the potable water supply.

Backpressure may be created when a source of pressure, such as a pump, creates a pressure greater than that supplied form the distribution system.  If a pump supplied from a non-potable source, such as a landscape pond, were accidentally connected to the plumbing system, the non-potable water could be pumped into the potable water supply.

How to Prevent Contamination of Your Drinking Water

Protect your drinking water by taking the following precautions.


  • Submerge hoses in buckets, pools, tubs, sinks, or ponds.
  • Use spray attachments without a backflow prevention device.
  • Connect waste pipes from water softeners or other treatment systems to the sewer or submerged drain pipe.
  • Use a hose to unplug blocked toilets or sewers.


  • Keep the ends of hoses clear of all possible contaminants.
  • If not already equipped with an integral (built-in) vacuum breaker, buy and install hose bibb type vacuum breakers on all threaded faucets around your home.
  • Install an approved backflow prevention assembly on all underground lawn irrigation systems. Remember, a plumbing permit is required for the connection of an underground lawn irrigation system to your plumbing system.

Protection of the Public Water Supply System

In general, the installation of plumbing in compliance with the plumbing code will provide adequate protection for your plumbing system. Also, washing machines and refrigerator ice makers already incorporate backflow prevention.

The Columbia Valley Water District will inspect each property to ensure there is adequate protection for the public water system. 

Hose Connection Vacuum Breaker
Hose connection vacuum breakers are specifically made for portable hoses attached to hose thread faucets. Their purpose is to prevent the flow of contaminated water back into the drinking water. These devices screw directly to the faucet outlet. They can be used on a wide variety of installations, such as service sinks, hose faucets near a wading pool, laundry tub faucets, etc.

Some units are designed for manual draining for freezing conditions.  Some are furnished with breakaway set screws as a tamper proof feature.   All hand-held shower heads shall be hung up properly to prevent possible cross connection. These devices are not intended for operation under continuous pressure.

Colmbia Valley Water District

6229 Azure Way

Maple Falls, WA 98266

PHONE:  (360)599-1699

FAX:       (360)599-1854



Our Business Hours

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08:00 am - 12:00 pm

01:00 pm - 04:30 pm

After Hours Emergency


 Pager:  (360)714-3558

(Dial your phone number after the beep.)