Department of Public WorksPublic Services Building
2650 LaFranier Road
Traverse City, MI 49686
Michael Slater, Director of Public Works
Keeping our Grand Traverse County Drinking Water Safe for human consumption.
What is Backflow?
The Michigan Safe Drinking Water Act, 1976 P.A.399, defines "backflow" as water of questionable quality, wastes, or other contaminant entering a public water supply system due to reversal of flow.
Backflow protection prevents undesirable water, sewage, bacterial, pathogens, or chemical solutions from entering your drinking (potable) water system.
Backflow and back siphonage are two known and preventable causes of water contamination.
Backflow is the reversal of normal flow due to backsiphonage or backpressure.
Backsiphonage occurs when a vacuum is induced (a stoppage in the water supply), like drinking from a glass through a straw.
Back siphonage can be caused by:
- Watermain breaks or repairs at lower elevation than the service point
- High water flow from the water system, such as a break in the line, or firefighting use
- Undersized piping
Backpressure on the flow happens when downstream pressure is greater than the supply pressure.
Back pressure can occur when the following connections are made to the drinking water system:
- A non-potable system with pumping system is inter-connected
- Heat exchange
- Steam or hot water boilers.
Contamination of the public drinking water supply is a health hazard; a consumer is being subjected to potentially lethal water borne disease or illness.
Common water use that could pose a threat to drinking water include:
- Hose connections to chemical solutions
- Lawn irrigation and sprinkling systems
- Chemically treated heating systems
- Water softeners
- Hose connections to contaminated water as in a laundry tub
- Swimming pools
- Solar heating systems
- Private non-potable water supplies
- Non-approved ballcock assemblies in toilets
- Water operated sump drain devices
What is the Law?
The Michigan's Safe Drinking Water Act, P.A. 399, 1976 (As Amended), Michigan Plumbing Code 2009, and local government Cross Connection Control Ordinances that require backflow prevention device installation and regular testing. It is the property owners responsibility to ensure that backflow prevention devices are properly installed, and tested in compliance with Act 399 of 1976, as Amended. The website link to this Act is:www.michigan.gov/Agencies/DEQ/Drinking Water/Community Water Supply.
Questions concerning backflow prevention may be directed to:
- Grand Traverse County Department of Public Works at 231-995-6039
- Michigan Department of Public Health-Division of Water Supply at 517-335-9216
- Michigan Department of Labor - Plumbing Division at 517-322-1804
- Grand Traverse Construction Code Office - Plumbing at 231-995-6049
Backflow Prevention Devices, Testing:
All testable backflow devices are to be tested upon installation, and tested annually thereafter. The local ordinance may require more frequent testing based upon degree of hazard, corrosive atmosphere or concerns with water quality.
Testable devices are:
- Double Check Valve Assembly Reduced Pressure Backflow Preventer Assembly
- Reduced Pressure Detector Assembly Spill Resistant Vacuum Breaker
- Double Detector Check Valve Assembly Pressure Vacuum Breaker
Testers certified by the State of Michigan shall test and install backflow prevention devices. An area listing of Certified Testers is available from the following website: mpmca.org. Select the "Certified Backflow Testers" option, type in Grand Traverse in the "County" selection, and hit the "search" button.
Testing varies by device type and typically takes 10-30 minutes. The water supply to the backflow preventer is turned off during testing.
Links to additional information regarding backflow and cross connections:
- The MDEQ Cross Connection Rules Manual can be found at the following website: www.michigan.gov/Agencies/DEQ/Water/Dringing Water/Community Water Supply/ Cross Connection Rules Manual - Fourth Edition.
- For information on the State Plumbing Code go to: www.michigan.gov/LARA.
- The United States Environmental Protection Agency has much useful information on the following website: www.epa.gov and search "cross connections".