Backflow Prevention Device Annual Test Program

General Information and Requirements

The State Department of Health and Environment regulations requires the City of Patterson Cross Connection Control Program to test all backflow prevention devices installed on the City Water Infrastructure. The City tests its own backflows and those private devices with authorization from property owners.

How to Notify the City of your intent to Test

Periodic Test and Maintenance letters will be sent out to all property owners and responsible parties in January of each year. Letters were mailed out to all affected parties on January 20, 2026.  Parties are able to respond either by calling (209) 895-8060 or emailing lcamara@pattersonca.gov. Property Owners that do no respond and notify the City of their selected approved outside tester, will authorize the City to perform the tests for 2026. The response deadline is noted on the letter.

Approved Outside Testers

The City does not accept backflow tests from outside testers that have not been approved by the Public Works Department. A current list of approved backflow testers are as follows:

Backflow Tester’s New to the City of Patterson

Forms can be downloaded for submission, or an electronic application can be submitted by clicking on the application link below, however, a business license is required to complete the process.

Application to become an approved tester (PDF)

Information about our program (PDF)