Backflow Prevention

Backflow is the reversal of the normal direction of flow which results in undesirable materials entering the water system. Backflow can occur whenever the water pressure is reduced enough to cause a vacuum or "back-siphonage." The same principle is involved when drinking through a straw. Some situations which may cause this include: watermain breaks or shut down for repairs, hydrants opened for flushing or fire fighting, undersized piping in your residence, or your water shut off for repairs. Another form of backflow, called "back-pressure" occurs when the down stream pressure becomes greater than the supply pressure. This can be caused by things like: pumps, boilers, and heat exchangers.

Cross Connection


A cross connection is an arrangement of piping or appurtenances through which backflow could occur. Think of the items in and around your home which contain things you wouldn't want to drink, like: sewer lines, bathtub, mop bucket, etc. Any water connection to these items forms an avenue through which the contents may backflow into the drinking water system. There are numerous instances where this has caused illness and death.

Cross Connection Prevention


Cross connections are prohibited by State and local plumbing codes. Additionally, Michigan water utilities are required to have a cross connection control program. Our utility does have a comprehensive program for the inspection, elimination and prevention of cross connections in industrial, commercial and public facilities. However, like most utilities, the manpower is not available to carry out an effective residential inspection program. That is why we are asking you to help protect yourself and your neighbors by eliminating your cross connections.

Common Cross Connections


The most common cross connection(s) in residences are made with an ordinary garden hose. Hoses are used in a variety of potentially hazardous situations such as: chemical sprayers, laundry tubs, detergent aspirators, radiator flushing, flushing clogged sewer pipes, swimming pools, and many more.

Some other cross connections to look for include: underground lawn sprinkler systems, irrigation pumps, chemically-treated heating systems, water softener drain lines to sewer, water operated sump drain devices, non-code (siphonable) ball cock assemblies in toilets, shower hoses, and solar heating systems.

What You Can Do


You should become familiar with the water system in your residence. Look at every usage point and visualize what might happen if the flow suddenly reversed from the normal direction.

You can install inexpensive hose bib (faucet) vacuum breakers to prevent back siphonage through hoses. The drain line from your water softener can be shortened or suspended so that there is an air gap between it and the sewer pipe. In other instances, you may need professional assistance in determining the appropriate protection against backflow.

If at any time you suspect a backflow has occurred, notify the Coldwater Board of Public Utilities immediately.