Irrigation & Backflow Prevention


Backflow prevention devices prevent drinking water contamination, which could occur, for example, if water from an irrigation system, pool or other use flows back into the town’s drinking water supply. The devices prevent cross connections between the Town's water system and a private water system.

Backflow prevention devices use a system of check valves to prevent water and potential contaminants (for example, from the irrigation system or swimming pool) from being forced backward into the Town's drinking water supply.

For more information on device requirements or standards, permits, and inspections, contact the Department of Public Works at (919) 552-5920. 

Getting a Residential Backflow Prevention Device Certified

A letter will be mailed to residents with backflow prevention devices 30 days before certification is due. Residents contact a certified tester not affiliated with the town to complete the inspection. The tester will confirm the device is in working order and submit test results directly to Backflow Solutions Inc., which manages backflow prevention device data for the town. If a resident does not wish to have a backflow prevention device tested, a request can be made to have the second meter turned off to stop using water from that meter.

Test Submission

Backflow test reports are submitted directly to Backflow Solutions Inc. at

Importance of Backflow Prevention Devices

A cross connection is any physical connection that ties the public drinking water system with another source of water or water system that has questionable water quality. For residential property, some examples of cross connections include irrigation systems or swimming pools and the usage of well water. Cross connections also may occur on residential properties in some home-based businesses, for example in film processing labs and hair salons. 

A break in a water line or a firefighting effort causing a loss of pressure in the town’s drinking water system could result in a backward flow of water. Backflow also could be caused by an increase of pressure in the resident’s system. Backflow prevention devices prevent water from flowing back into the town's drinking water supply.

Cross Contamination

State law requires municipalities create cross connection programs and to monitor which properties need backflow prevention devices and ensure the devices are being maintained. To ensure the continued quality of the Town's drinking water supply and to comply with state law and the Federal Safe Drinking Water Act, Holly Springs requires residents and businesses that have water systems with the potential to contaminate the public drinking water supply to install backflow prevention devices. 

The only way to guarantee that backflow prevention devices continue to operate properly is to inspect them regularly, as manufacturers recommend. Federal and state water quality agencies recommend annual testing, and many surrounding municipalities require it.

The Holly Springs Town Council adopted an ordinance that requires consumers with potential cross connections to install backflow prevention devices and to have backflow prevention devices tested by a certified inspector. 

Backflow prevention devices have been required and cross connection control programs have been in place in Raleigh since 1985, in Durham since 1987, in Apex since 1993, and in Cary since 2003.