Customer shall contract with a WA State certified tester. The Washington Certifications Services (WCS) website provides a listing of backflow assembly testers by County

  • Customer hired tester to provide City with the following:
    • COBI Business License
    • WA State Backflow Assembly Tester Certification
    • Test Equipment Calibration Report
    • WA State Contractor’s Registration
    • Verification of liability insurance.
    • Tester shall use COBI’s Backflow Prevention Assembly Test Report

For your convenience a list of companies that have provided their contact information to the City and are shown on the WCS website is shown below:

When are the annual backflow assembly tests due?
The City will send a reminder notice to the property owner when testing is due.

Water Customer Responsibilities
The customer is responsible to have each backflow assembly located on their premise tested annually and for submitting an original backflow certification report for each backflow assembly tested (most testers and/or testing companies submit the backflow certification report on behalf of the customer). If customer hired backflow tester is contracted, the test report must be delivered to the City of Bainbridge Island Operations & Maintenance Division within 30 calendar days.

Backflow Test Device Gauge
For customer hired testers, test equipment used for the purpose of testing a backflow assembly shall be recognized and approved for such use by City and State standards.  No test gauge shall be used for the testing of a backflow assembly that has not successfully passed a valid calibration test within the 12-month period of the date on the backflow assembly report.

Each backflow device tester and/or testing company shall forward to COBI Operation & Maintenance Division a valid original calibration test report for each gauge under their control.  The calibration report form shall include the calibration company name, address, telephone number, and the name of the person performing the test with their signature.  The report should also include gauge manufacturer name, model number, serial number, owner, and the date of calibration.  The calibration report shall indicate the test standards used in the calibration of the gauge.