Cross Connection Program


In accordance with the Safe Drinking Water Act of 1974, the Wisconsin Department of Natural Resources (WDNR), under NR 81.15, requires municipal water suppliers to develop and implement a comprehensive cross-connection control program for the elimination of all existing cross-connections as well as the prevention of future cross-connections.

The Brown Deer Water Utility delivers safe, high-quality drinking water every day. However, outside contaminants and pollutants have the ability to degrade the quality of the drinking water supplied and serve as a health and safety risk. The Brown Deer Water Utility’s Cross-Connection Control (CCC) program is designed to continue to safeguard public health and keep the water system safe from contaminants and pollutants.

Brown Deer Utility operators perform inspections of all commercial, industrial, multi-family, public authority, and residential buildings connected to the water supply to detect actual and potential cross connections and make recommendations for the installation of backflow prevention devices or assemblies where necessary. There inspections happen on varying frequencies based on the hazard level of the facility. The frequencies are shown below.

Building Type/RiskInspection Frequency
Residential (Low Risk)20-year cycle
Commercial, Industrial, Multi-family, Public Authority (Low Risk)6- or 10-year cycle
Commercial, Industrial, Multi-family, Public Authority (High Risk)2-year cycle

The Brown Deer Water Utility coordinates residential inspections with the Public Service Commission (PSC) of Wisconsin’s mandatory meter replacement program. Therefore, when a residential water meter is replaced at the end of its 20-year lifespan, a cross-connection inspection will also be performed.

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 system to a faucet or other plumbing fixture. Under certain conditions, water can flow in the reverse direction. This is known as backflow, and it occurs when backsiphonage or backpressure is created in a water line.

Back-siphonage may occur when there is a drop in the supply pressure of the water distribution system. This can be caused by a water line break, water main repair, or during a rapid withdrawal of water from a fire hydrant. This creates a vacuum, which may pull or siphon contaminants or pollutants into the drinking water supply.

Backpressure may be created when a source of pressure, such as a pump, boiler, or other building creates a pressure greater than that supplied from the water distribution system; this may force water to reverse direction.

More Information

For more information on cross-connections and how to prevent them, please look at the following links:

For more information on the Brown Deer Water Utility CCC program, click here.