Backflow testing for Estero MID customers
Estero Municipal Improvement District (Foster City’s water supplier) requires an annual test by a tester on San Mateo County’s authorized backflow tester list, as part of the County’s cross-connection program. BackflowCare tests assemblies for Estero MID customers in Foster City, and files the results with Estero MID.
- Area
- San Mateo County
- Cities we serve
- Foster City
- Annual test
- Owner hires a certified tester
- Deadline
- The tester sends the test report to County Environmental Health within 10 calendar days.
- Estero MID 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)
Estero MID testing rules
- In the San Mateo County program, only a County-certified backflow tester may test assemblies.
- Assemblies must be tested at least once a year, and again after installation or repair.
Source: San Mateo County Environmental Health cross-connection program (official page), checked October 19, 2026.
Estero MID backflow questions
Who tests backflow devices for Estero MID customers?
Estero Municipal Improvement District (Foster City’s water supplier) requires an annual test by a tester on San Mateo County’s authorized backflow tester list, as part of the County’s cross-connection program.
Which cities does Estero MID serve?
We serve Estero MID customers in Foster City.
When is the Estero MID backflow test due?
The tester sends the test report to County Environmental Health within 10 calendar days.
Does Estero MID 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.