Residential Backflow Prevention Assembly Testing Program

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To protect the Town's water system, the Town of Cary's Cross Connection Control Ordinance requires all single-family residential irrigation customers to have an approved backflow prevention assembly installed and tested annually.

To assist customers, the Town conducts a Residential Backflow Assembly Testing Program that coordinates and manages the annual process. Residential irrigation customers are automatically scheduled for testing conducted by Town-certified backflow technicians and will receive a letter with program details in advance of the start date.

If you prefer to coordinate your own testing, you can opt out of the Town-coordinated program and complete the required testing using an approved tester of your choice.  

Opting Out of the Program

Customers who do not want to participate in the program must inform the Town of their decision each year.

  • On the Web:  Use our online opt-out form and submit your name, address, and contact information.
  • By phone: Call (919) 469-4090 from 8 a.m. to 5 p.m. to speak to a customer service representative.    

Town-Coordinated Testing

Testing begins in May and is usually complete by September. The Town currently contracts with Commercial Services, Inc. to conduct this service. Commercial Services, Inc. staff will be in uniform with visible identification and drive vehicles with a "Town of Cary Contractor" magnetic placard affixed to the driver's side.

Learn when technicians will be in your area


  • Testing requires a 15-minute interruption of water service and utilizes less than one gallon of water.
  • The technician will leave a door hanger with results once the test is complete.
  • It is not required for you to be home during the testing.


  • The program fee is $50 and includes an internal repair kit, if needed.
  • The fee will appear on your utility bill following the completion of testing.

Limits of testing

  • If your assembly is damaged beyond repair and has a failed test result, you will be responsible for contacting a plumber to repair or re-install the assembly, having it tested and submitting results to the Town of Cary.
  • If your assembly is located inside the crawl space of a building, under decks, inside a shed, or in a closed restricted access or structure, you will be responsible for arranging your own test and submitting results to the Town of Cary. You must opt out of the Town coordinated program and complete the required testing using a Town of Cary approved tester of your choice.

Discontinuing Irrigation Service

If you discontinue the use of an irrigation system, you have the option to remove a separate irrigation meter at no cost; call Town of Cary at (919) 469-4050 to make your request.

If you do not have a separate meter, you can contact a licensed plumber to disable and cap off the irrigation below grade. This action requires a plumbing permit and inspection by a Town of Cary plumbing inspector; call the Inspections and Permits department at (919) 469-4030 for more information.


Town of Cary
(919) 469-4090
Service Request Portal

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