Backflow Prevention

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Backflow Prevention Basics

In 1987, the Department of Natural Resources established a drinking water regulation entitled “Prevention of Backflow.” This regulation places certain responsibilities on owners of backflow prevention devices. There is a potential for cross-connection backflow contamination of the public drinking water supply with lawn irrigation systems, car washes, medical facilities, fire suppression systems, etc. The Department of Natural Resources defines “backflow” as “the unwanted reversal of flow in a water distribution system or a piping system inside a customer’s premises due to changes in the hydraulic pressures of the system.”

Two factors are essential for backflow to occur. First, there must be the interruption in the normal direction of flow in the distribution system. Second, there must be a link, or connection, between the potable drinking water system and the source of contaminant.

If you own a backflow prevention device, it must be inspected and tested annually.

Have your tester forward the report and fee to:

St. Louis County Department of Public Works
Attention: Cindy Basham
41 South Central
St. Louis, MO 63105-1719

Please feel free to contact us, St. Louis County Department of Public Works, or the Missouri Department of Natural Resources Public Drinking Water Program (address and web site listed above), for more information regarding the basics of backflow prevention.

Helpful “Tips”

  • Don’t obstruct that meter pit cover! The round meter pit cover in your yard serves an important purpose. Please don’t cover it with landscaping materials or mulch. Meter reading and maintenance personnel need to access that cover in order to perform a variety of jobs related to your water meter. Obstructing your meter pit cover could result in estimated and inaccurate water bills.
  • High water bill? The majority of high water bills are usually due to undetected leaks. The number one culprit? A leaking toilet. The American Water Works Association has some interesting facts about residential water usage. Feel free to visit their web site, listed in this section.

Recommended Websites For More Information

American Water Works Association
6666 West Quincy Ave.
Denver, CO 80235

Missouri Department of Natural Resources
Public Drinking Water Program
P. O. Box 176, Jefferson City, MO 65102

U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC 20460

Metropolitan St. Louis Sewer District
2000 Hampton Ave.
St. Louis, Mo. 63139