Are You Preventing Contaminants from Entering the Water Supply?

Backflow preventer devices are necessary for homes with lawn irrigation systems and pools.

Wednesday, Jan. 4, 2023
Image of man with utilities box housing backflow preventer device
In a town video, Utilities Infrastructure Protection Supervisor Troy Miller shows what backflow prevention boxes look like, where the devices are located, why they’re needed and how they must be maintained.

Ever wonder what those large utility boxes are in some yards and in front of some buildings? They may house a backflow preventer device, which prevents water and possible contaminants from flowing back into the town’s water system.

Commercial facilities are required to use backflow preventers, but they’re also necessary for homes with lawn irrigation systems and pools. A properly operating backflow device allows flow in one direction, preventing contaminated water from entering potable water in a building during sewer system maintenance or backups.


The devices can be protected in winter with pipe insulation, an insulated cover or a heat lamp and heat trace tape. All backflow devices are required to be in a class 1 or 2 enclosure that meets the American Society of Sanitary Engineering’s 1060 standard. These enclosures help protect against frost and freezing. Backflow devices for irrigation can be removed for winterization, but they must be retested when reinstalled in the spring. 

The state requires annual testing of the devices as well as testing of new installations. The town contracts with Backflow Solutions Inc. to manage its backflow test data. It is the property owner’s responsibility to contact a licensed backflow tester and to have the results submitted to Backflow Solutions. For a list of licensed, registered testing agencies, visit BSI Online.

More information

For more information on backflow prevention:

  • See FAQ: Backflow Prevention.
  • See our backflow prevention assemblies video.
  • Contact Utilities Infrastructure Protection Supervisor Troy Miller by email or at 919-296-9653.

For more information on testing, contact Backflow Solutions at 800-414-4990 or