Cross Connection Control Program

Cross Connection Control Program

The Oakland County Water Resources Commissioner's (WRC) Cross Connection Control Program (CCCP) is designed to protect drinking water. It does that by preventing contaminants from entering the public water supply system through a reversal of flow (backflow or back-siphonage). A pollutant or contaminant may enter the water supply when the pressure of the pollution source is greater than the pressure of the water supply or when there is a sudden loss of pressure in the water system.  These pressure fluctuations can be caused by hydrant flushing, water main breaks, power outages, or a number of other factors. In order to ensure safe drinking water, backflow prevention devices are required at all connections where the water may be exposed to a pollutant or contaminant.

Several examples of potential cross connections are garden hoses, toilets or toilet fill valves, lawn sprinkler systems, laundry tubs, swimming pools, hot tubs, boiler systems, water assisted sump pumps and fire sprinkler systems. Common household cross connections are caused by the misuse of garden hoses, such as leaving the end of the hose submerged in swimming pools, attached to chemical sprayers or laying on the ground. Without the proper backflow prevention devices these misused garden hoses can expose the water supply to cesspools, pesticides or garden chemicals and animal feces. Although numerous cases across the world have been documented (see links below), many more cases are left unreported.

The CCCP is run in accordance with the Michigan Department of Environmental Quality (MDEQ) and the State of Michigan Public Act 399, 1976 Rule #325.11401 through Rule #325.11407 of the Administrative Code. Our program is approved by the MDEQ and has been in effect in Oakland County since 1976. The onset of our program focused on commercial and industrial facilities and was expanded in 2002 to include residential customers.  This update occurred in response to changes in State rules and regulations in an effort to better protect our potable (drinking) water systems from pollution or contamination.

Helpful definitions:

a) Cross Connection: A temporary or permanent connection or arrangement of piping (link) between a potential source of pollution and a potable water supply through which a backflow could occur.

b) Backflow: A reversal of water flow from its normal or intended direction that may contain water of questionable quality, wastes or other contaminants and which may then enter the potable water supply.

c) Back-siphonage: Backflow caused by a negative pressure (partial vacuum) in the supply piping that may contain contaminated or polluted water. The effect on flow is similar to drinking water through a straw.

d) Backpressure: Backflow caused by a downstream pressure that is greater than the upstream (or supply system) pressure.

e) Potable water: Water suitable for drinking.

How is WRC working to prevent cross connections?

Our Cross Connection Unit has a State-approved comprehensive program designed for the inspection, elimination and prevention of cross connections in commercial and industrial facilities along with residential homes. Our staff performs these inspections, which are included in your water rates, at a minimum interval of once every one-to-10 years. If our staff finds a cross connection, the customer will be notified by mail. This letter may provide a notice to install a proper backflow prevention device or have the existing one properly installed and/or tested by a certified tester. Any repairs, installation and/or testing are at the expense of the homeowner or business. Many backflow prevention devices are required to be tested (click here for WRC test form) annually in order to ensure they are working properly. These backflow prevention devices have internal seals, springs and moving parts that are subject to fouling, wear or fatigue and must be maintained in proper working order.

Helpful hints for the installation and/or testing of backflow prevention devices:

Comparison shop! Contact several companies and ask for a quote over the phone. Click here for WRC List of Certified Testers.

Some items to ask when contacting a company to perform the installation/repair and/or testing:

  • Do you charge a "trip" fee (a site visit fee)?
  • What is the charge to test the device?
  • What if my device fails, do you charge an additional fee if it needs service for items such as spider webs, dirt, or to replace a seal?
  • What is the charge if the device needs significant repairs or to be rebuilt? Is there a charge to retest my device after it's been serviced and/or repaired?
  • What is the charge to install a new device and is testing included in that price?
  • Is a permit from my municipality required and is there a fee involved?

*This information is provided as a courtesy and is not intended as an endorsement or referral. The businesses provided on this website have no affiliation with the Oakland County Water Resources Commissioner's Office. You are responsible for any and all services rendered by your contractor/plumber.

Remember, your completed WRC Device Test Forms can be faxed to our office at 248-858-7939 or emailed to:

How can you help prevent a cross connection?

There are many simple things each of us can do to help prevent cross connections in and around our homes or places of business. Become familiar with your water piping system. Review every water connection in the building and visualize the result if the water flow reversed. Install the necessary backflow prevention devices and keep them maintained, tested and in proper working order.

A few examples of typical water connections to review for proper protection are outside faucets/hose bibbs, toilets or toilet fill valves, lawn sprinkler systems, swimming pools, water-assisted sump pumps and boilers. If not properly protected against backflow, these water connections may cause polluted and/or contaminated water to enter the potable water supply. This can result in illness and even death.

In addition, private wells that are also connected to the potable water supply are a direct cross connection and prohibited. The piping from a well must be permanently disconnected from the potable water supply. The well may still be used as a secondary source of water as long as it is not in any way connected to the public drinking water supply.


  • Have you ever filled a bucket of soapy water with a hose and mistakenly left that hose submerged in the bucket?  
  • Ever attached a chemical sprayer to the end of your hose to fertilize your garden?

In doing so, without the proper backflow protection on the hose, you are unknowingly creating a cross connection. Those chemicals, pollutants or contaminants from the submerged end of that hose or connection can be drawn right back into the drinking water. No one wants to drink soapy water or fertilizer! One particularly easy way to prevent that is by installing an inexpensive hose bibb vacuum breaker on the hose connection or even by simply maintaining a minimum 1 inch air gap between the end of the hose and the source of potential pollution.

  • Do you have a lawn sprinkler system connected to the potable water supply? Is the proper backflow prevention device installed, maintained and routinely tested by an approved certified tester?

Think of all the pollutants and contaminants your lawn may be exposed to: fertilizer, soaps, animal feces, bugs, dirt, etc. If the proper backflow prevention device does not exist or is not properly maintained, these pollutants or contaminants may flow right back into the drinking water!

Still have questions?

Please feel free to contact our Cross Connection Unit at:

IPP/Cross Connection Unit
Oakland County Water Resources Commissioner’s Office
One Public Works Drive
, Bldg 95W
, MI  48328-1907

Residential customers: 248-858-1431 or email:
Commercial customers: 248-858-9387

Fax: 248-858-7939

Remember, by working with us to protect the water quality, you will be protecting yourself, your family and your neighbors!

See below for additional links and educational resources:

Click here for a blank WRC Device Test Form.

Click here for examples of several backflow prevention devices.

Click here for our WRC Cross Connection brochure.

Click here for the link to the MDEQ Cross Connection "Protecting our Public Water System" brochure.

Click here for the Watts Industries brochure.

Links to certified backflow prevention device testers:

ASSE Certified Testers

Michigan Plumbing and Mechanical Contractors Association Testers

WRC List of Certified Testers

*This information is provided as a courtesy and is not intended as an endorsement or referral. The businesses provided on this website have no affiliation with the WRC. You are responsible for any and all services rendered by your contractor/plumber.

Links to documented backflow cases:

Backflow cases

Backflow Prevention TechZone

Additional Resources on the Web: