Hose Connection Vacuum Breakers
A simple low-cost device known as a hose connection vacuum breaker, or HVB, can be installed on your outside faucets to prevent backflow of contaminated water into the Island's water supply. Backflow, which is backward movement of water, can occur either by siphoning or back pressure, that is, when the pressure in a garden hose exceeds that in the water supply pipeline. Examples of sources of potential contaminants to the water supply include hot tubs, irrigation systems, and garden sprayers.
An HVB is easy to install as shown in the following illustration. Simply thread the HVB assembly onto the male hose threads of the faucet or hose bibb. Then connect the garden hose onto the male threads of the HVB.
The HVB works to prevent backflow to the water supply by venting water to the atmosphere (onto the ground) when backflow conditions exist. Important: The spring-loaded check valve in the HVB does not allow drainage of water from between the hose bibb and the upper part of the HVB. Thus freeze protection must be provided, just as all outdoor plumbing must be protected under freezing conditions.
Hose backflow protection is now required for all new construction by the building code. Typically, freeze-proof faucets are used with the HVB device built in. It should be noted that hose backflow protection is only a part of the larger subject of protection against cross-connection hazards. Your water distribution team will be supplying you with more information about cross-connection in the coming months.
Locally, HVBs are available at the Silverdale Home Depot for about $4 plus tax. Home Depot carries the Zurn/Wilkins model BF9-8. HVBs are also available from plumbing supply companies like Rosen's in Bremerton, but the price is a little higher.