Backflow testing for San Mateo County customers
Environmental Health runs the backflow program for a number of San Mateo County water suppliers under contract, and only a County-certified backflow tester may test assemblies in its jurisdiction. BackflowCare tests assemblies for San Mateo County customers in San Mateo County, and files the results the way San Mateo County requires.
- Area
- San Mateo County
- Annual test
- Owner hires a certified tester
- Filing results
- The tester sends the field test report to Environmental Health within 10 calendar days of the test.
- Deadline
- The first notice goes out 30 days before the anniversary test date; an assembly not tested within 30 days after that date is delinquent.
- San Mateo County fee
- Late testing can bring administrative fines of up to $500 per day, per assembly.
- Our price
- $199 per device ($25 off for new customers)
- San Mateo County contact
- backflow@smcgov.org, 650-372-6200
San Mateo County testing rules
- Assemblies must be tested at least once a year, and again after installation or repair.
- Testers need a backflow tester certification from AWWA California-Nevada Section (or an equivalent the County accepts) and must pass the County exam.
Source: San Mateo County Environmental Health Services – Cross-Connection Control Program backflow program (official page), checked October 17, 2026.
San Mateo County rules for new and replacement devices
- Only USC-approved assemblies may be installed, with at least one foot of clearance between the assembly’s lowest point and the ground or floor.
San Mateo County backflow questions
Who tests backflow devices for San Mateo County customers?
Environmental Health runs the backflow program for a number of San Mateo County water suppliers under contract, and only a County-certified backflow tester may test assemblies in its jurisdiction.
How are backflow test results filed with San Mateo County?
The tester sends the field test report to Environmental Health within 10 calendar days of the test.
When is the San Mateo County backflow test due?
The first notice goes out 30 days before the anniversary test date; an assembly not tested within 30 days after that date is delinquent.
Does San Mateo County charge a backflow fee?
Late testing can bring administrative fines of up to $500 per day, per assembly. It is separate from our $199 test price.