Looking for a backflow tester in San Mateo, CA? Describe your project once and up to three certified backflow testers who work in San Mateo and San Mateo County get back to you with a quote. It's free and there is no obligation.
San Mateo is home to about 103,006 people (2024 Census Bureau estimate), a shrinking community (−2.5% since 2020). With 8,489 people per sq mi, it is a densely built-up area. Businesses, irrigation systems and multifamily buildings here must test their backflow assemblies every year.
San Mateo at a glance
- Population (Census Bureau estimate, 2024)
- 103,006 (−2.5% since 2020)
- Rank in California
- 71st of 482 cities and towns
- Land area
- 12 sq mi
- Population density
- 8,489 people per sq mi (densely built-up)
- Type
- City (San Mateo city)
- Main county
- San Mateo County
What to check before hiring in San Mateo
- Approved list: check your utility's list of certified testers.
- Report: ask the tester to file the report with the utility and send you a copy.
- Failed test: repairs are done by a licensed plumber, followed by a retest.
- Price drivers: number and size of devices, repairs and access.
Useful official resources
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ABPA: American Backflow Prevention Association
Official information and guidance.
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IAPMO: plumbing codes
Official information and guidance.
Services available in San Mateo
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Annual backflow test
Test of backflow prevention assemblies with the report filed with the water utility.
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Backflow repair or installation
Repair of a failed assembly or installation of a new one by a licensed plumber.
Frequently asked questions in San Mateo
How much does backflow testing cost in San Mateo, CA?
It depends on the number and size of devices. Describe your property: testers who serve San Mateo reply with a quote.
How long does a test take?
Usually under an hour per device.
Will my water be turned off?
Briefly, during the test.
Which certified backflow testers will contact me?
Up to three independent certified backflow testers who serve San Mateo and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.