Cross Connections in Household Plumbing Systems

A cross-connection is a connection between the public water supply and any other unprotected source, which may contribute to the contamination of public drinking water. Brookesmith Special Utility District and Brown County Water Improvement District #1 work hard to provide the safest drinking water possible to your home. However, once this water enters your property, there are common problems that may arise due to improper changes in, or misuse of, your plumbing system.

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Have you ever considered all of the places that you use water in your home? You may be surprised how may different ways that water can be used, and possibly misused. Here are a few of the uses of water that you might want to pay more attention to in order to protect the purity of the water you drink, cook with, or bath in.

Sinks, Tubs, Tanks (water troughs)

The faucets in your bathroom or kitchen must be located so that the end of the faucet is above the overflow level of the sink or tub. Fill lines to water toughs or tanks must also be physically separated or "air-gapped." If there is no air-gap, then the contents of the sink, tub, or tank may be sucked or "backsiphoned" into the water line during a loss of water pressure. See Sinks, Tubs & Tanks Illustration below. 

Hose Bibbs

Hose bibbs are part of everyday life. They allow us to hook up a garden hose to water the plants, wash the car, clean out the gutters, fill the swimming pool, etc. However, everytime you connect a garden hose to a hose bibb, you are extending the end of the water line. To make sure that no harmful materials are drawn back into the garden hose, a vacuum breaker should be installed on each hose bibb. When the hose bibb is exposed to freezing conditions, make sure to use a self-draining, frost-proof vacuum breaker. See Hose Bibbs illustration below.


Toilets need water to flush the waste material into your septic tank. The water that flushes the toilet enters into the toilet tank from the small hose or pipe connected to the toilet tank. It is essential that the float-valve (or anti-siphon ballcock) inside the toilet tank is the correct type so that the contents of the toilet tank don't get back into the drinking water system of your house. As shown in the Toilets illustration below, the anti-siphon ballcock and refill tube must be above the water level in the tank. 


Irrigation systems make watering of your lawn or garden much easier, but if not properly constructed, contaminants may backflow into your drinking water. Backflow protection may be provided with vacuum breakers, (atmospheric (AVB) or pressure (PVB or SVB)) or reduced pressure principle assemblies (RP). See Irrigation illustration below.

Water pooling around sprinkler heads may be contamined by chemicals, fertilizers, or animal waste.


NOTE - Make sure to use only AWWA listed or approved products. Should you have any questions regarding the selection or installation of proper backflow protection, check with BSUD or a licensed plumber.