Irrigation & Backflow Prevention

Backflow prevention devices, which prevent cross connections between the Town's water system and a private water system, are required for all non-residential occupancies and for all lawn irrigation systems. For more information on device requirements or standards, permits, and inspections, contact the Department of Public Works at (919) 552-5920.
Backflow Prevention Devices Importance
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 may also occur on residential properties in some home-based businesses, for example in film processing labs and hair salons. Under certain circumstances and without the proper prevention devices, there is a possibility of contaminated water entering the public drinking water supply through the cross connection.

Cross Contamination
State law is now requiring municipalities to create cross connection programs that monitor which properties need devices that prevent potentially contaminated water from entering the public drinking water supply. The program will also make certain that the devices are 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, the Town, as part of the cross connection program, is requiring residents and businesses that have water systems with the potential to contaminate the public drinking water supply to install backflow prevention devices. Backflow prevention devices use a system of check valves to prevent water and potential contaminants from the secondary water system or source (for example, the irrigation system or swimming pool) from being forced backward into the Town's drinking water supply.

Backward Flow

Backward flow of water, also known as back-siphonage, can occur if there is a loss of pressure in the Town's water system. Loss of pressure can be caused by a break in a water main or by a firefighting effort, which uses a substantial volume of water. Backflow can also be caused by back-pressure, an increase of pressure in the customer's system that is greater than the pressure in the Town's system.

The only way to guarantee that backflow prevention devices continue to operate properly is to inspect them regularly, as manufacturers recommend. 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 November, 2003.