For Backflow Testers

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Redwood City’s Cross-Connection Control Program maintains a list of qualified backflow prevention assembly testers approved to perform required performance testing on all backflow prevention assemblies located within Redwood City’s service area. The City will only accept backflow test results from testers on the City’s Qualified Tester List. Testers must receive confirmation from the Cross-Connection Control Program of their status on the Approved List prior to testing an assembly. 

Qualified Tester List

Backflow Test Form

Qualified backflow assembly testers are required to use the City’s Backflow Prevention Assembly Field Testing and Maintenance Report for all backflow assembly performance tests.

Printed copies of the official test forms are available at:

Public Works Services
1400 Broadway Street
Redwood City, CA 94063 

Backflow assembly tests must be reported on the City's Backflow Assembly Device Field Testing and Maintenance Report within 15 days of completion, and must be submitted on the official City form or they will be rejected. 

Test reports are due to the City within 30 days from the City's first notice to customer. If an extension is required, the customer is responsible for contacting the City in writing.

Test Reports shall be submitted to the Cross-Connection Control Program by mail or in person at the address for Public Works Service above or by email to

Qualified Tester List

To be included on Redwood City's Qualified Tester List, testers must have on file with the Cross-Connection Control Program proof of the following items. Expired documentation will not be accepted, and it is the tester’s responsibility to provide updated documentation prior to expiration in order to be maintained on the City’s List.

  1. Redwood City Business License
  2. Proof of Insurance Coverage
  3. CA-NV AWWA Backflow Tester Certification
  4. Differential Pressure Gauge Test Kit Calibration Certification (required annually)
  5. Signed Application and Agreement for each Tester

Application and Required Documentation

Qualified Backflow Prevention Assembly Tester Application and Agreement (here)

Contact Us

Mail / In Person

Public Works Services
1400 Broadway Street
Redwood City, CA 94063

Apply for a Redwood City Business License

You can apply for a Redwood City Business License by submitting an application online, by mail or in person at City Hall. Visit the City's Business Licensing web page here.