Backflow Prevention

Backflow Prevention

Water line breaks or a sudden use of a large amount of water can cause low pressure in the buried pipes that are used to supply water to our customers.  When this happens the water in a consumer’s plumbing could be siphoned backward, potentially drawing contaminants into the public water system.

The City of Wilmington is required by Ohio state law to administer a backflow prevention program to protect the public water supply from this potential contamination.  The backflow program is designed to prevent the flow of water from a customer’s private piping back into the public water distribution system.

Certain plumbing installations pose a higher risk of contamination than others.  When a sufficient hazard exist a backflow prevention assembly must be installed by the customer.  This device prevents the consumer’s water from flowing backward in the supply line, maintaining a one-way flow of water.

Backflow Device Testing

The City of Wilmington, following state guidelines, requires that all containment backflow devices be inspected, tested and repaired, if needed, at least once every 12 months. While we accept other backflow testing forms, a link to our test form is provided for your convenience.

Test results are to be submitted to the City of Wilmington utility billing office by emailing results to or by mailing them to the following address.

City of Wilmington

Utility Billing Office

69 N. South Street

Wilmington, Ohio 45177

Attn: backflow administrator

Failure to perform required testing may result in termination of water service.  Backflow devices must be tested by an Ohio certified backflow tester.  The following link contains a partial list of backflow testers operating in Clinton County.

There is a $20.00 backflow administration fee assessed by the city for each backflow device.  This fee covers cost of administering our backflow prevention program.

Contact Information 

If you would like additional information or have questions about the backflow program call (937) 383-5518 or email

For more information on Backflow Prevention and Cross-Connection Control, please CLICK HERE.