Backflow Testing in San Mateo County, California
AWWA-certified annual backflow testing across every San Mateo County purveyor, with specialty coverage for SFO-adjacent cargo operations, the SSF / Foster City biotech corridor, and peninsula hospital campuses.
- CCL: #1062017
- AWWA Backflow Tester Cert.: #15112
- AWWA Specialist Cert.: #03373
- 16+ San Mateo purveyors covered
Serving: Redwood City, San Mateo, Daly City, South San Francisco, San Bruno, Pacifica, Menlo Park, Burlingame, Millbrae, Foster City, Belmont, San Carlos, East Palo Alto, Half Moon Bay, Brisbane, Colma, Woodside, Portola Valley, Atherton, Hillsborough.
Do I need backflow testing in San Mateo County?
If you have a backflow assembly on a San Mateo County service, yes. San Mateo is unusual: the County Environmental Health Services Division runs a consolidated program on behalf of most cities under County Code Chapter 4.72, while Cal Water, Redwood City, Coastside, NCCWD, and Montara operate their own parallel programs.
“Backflow prevention assemblies need to be tested at least annually in accordance to Section 3.3.3 of the State Water Resources Control Board Cross-Connection Control Policy Handbook and Section 4.72.070 of the San Mateo County Backflow Prevention Ordinance.”
The BAWSCA service area (which covers most of San Mateo County plus Santa Clara and East Bay wholesale) serves approximately 1,887,992 residents in FY 2024-25, and Cal Water’s three San Mateo districts alone account for ~70,000 service connections.
Not sure which utility serves your address? Call (800) 684-8346.
Water purveyors in San Mateo County requiring annual testing
An unusually dense mosaic: Cal Water districts plus city utilities plus special districts plus SMCEHS consolidated oversight.
| Purveyor | Service Area | Governing Rule |
|---|---|---|
| California Water Service — Bear Gulch District | Atherton, Woodside, Portola Valley, parts of Menlo Park, Ladera, Skyline, Kings Mountain | CPUC Tariff Rule 16 — Cross-Connection Control; SWRCB CCCPH |
| California Water Service — Mid-Peninsula District | San Carlos, portions of San Mateo | CPUC Tariff Rule 16; SWRCB CCCPH |
| California Water Service — South San Francisco District | South San Francisco, Colma, Broadmoor, small portion of Daly City | CPUC Tariff Rule 16; SWRCB CCCPH |
| City of Redwood City Public Works (Water) | Redwood City + Emerald Hills + portion of San Carlos | Redwood City program (independent of SMCEHS); SWRCB CCCPH |
| City of San Mateo | City of San Mateo | SMCEHS-administered under SMC Code § 4.72.070 |
| City of Daly City Water | City of Daly City | SMCEHS + SMC Code § 4.72.070 |
| City of Burlingame Public Works | Burlingame | Burlingame Municipal Code § 15.04.050 — Cross-Connection Control; SMCEHS partnership |
| City of San Bruno Water Department | San Bruno | San Bruno MC (Cross-Connection and Backflow Standards); SMCEHS partnership |
| City of Millbrae Water Department | Millbrae | Millbrae Municipal Code Chapter 8.10 — Backflow and Cross-Connection Control |
| Coastside County Water District (CCWD) | Half Moon Bay, El Granada, Miramar, Princeton, Moss Beach | CCWD Ordinance (CCCPH-compliant); independent program |
| North Coast County Water District (NCCWD) | Pacifica | NCCWD Ordinance No. 63-2025; SWRCB CCCPH |
| Mid-Peninsula Water District (MPWD) | Belmont + portions of San Carlos (~28,000 people) | MPWD Rules; SMCEHS + SMC Code § 4.72.070 |
| City of Menlo Park Municipal Water | City-operated portion of Menlo Park | Menlo Park Municipal Code Title 7, Chapter 7.28 (annual testing required) |
| Town of Hillsborough Water Department | Town of Hillsborough | Hillsborough Cross-Connection Control Plan; SMCEHS partnership |
| Montara Water & Sanitary District (MWSD) | Montara + Moss Beach | MWSD Water Utility Standard Specifications §16-05 (annual testing); SWRCB CCCPH |
| Estero MID (Foster City) / Brisbane Water (GVMID) / Westborough WD | Foster City / Brisbane / SSF unincorp. (3,882 connections, ~12,481 people) | SMCEHS + SMC Code § 4.72.070 |
“Failure to test a backflow prevention assembly as specified in Section 4.72.070 of the San Mateo County Backflow Prevention Ordinance may result in fines of up to $500 per day.”
How our testing process works
- 1
Identify your purveyor
Cal Water Bear Gulch / Mid-Peninsula / SSF, Redwood City, or an SMCEHS-administered city, CCWD, NCCWD, MPWD, MWSD, or Menlo Park.
- 2
On-site test (10 – 20 minutes)
Certified test procedure with calibrated gauges; we coordinate facility access for biotech / data center / airport sites.
- 3
If a device fails
We quote the repair on site and schedule the retest.
- 4
Report filed within 24 hours
We submit to SMCEHS, Cal Water, or the independent program as required, and send you a copy with the invoice.
- 5
Annual reminder
We track your anniversary date and reach out ahead of next year's deadline.
Devices we test
ASSE 1013
Reduced Pressure Assembly (RPA / RPZ)
High-hazard: biotech process water (Genentech, Gilead), data center cooling, hospital boilers and dialysis, SFO cargo cold-chain, tech campus cooling towers.
ASSE 1015
Double Check Valve Assembly (DCVA)
Residential fire lines, commercial irrigation without chemical injection.
ASSE 1020
Pressure Vacuum Breaker (PVB)
Above-ground irrigation protection — very common on peninsula residential and cemetery-landscape irrigation (Colma).
ASSE 1056
Spill-Resistant Vacuum Breaker (SVB)
Modern PVB variant; standard retrofit.
California and federal compliance context
“On December 19, 2023, the State Water Resources Control Board adopted the Cross-Connection Control Policy Handbook (CCCPH) with an effective date of July 1, 2024.”
52.3M
Passengers at SFO (located in San Mateo County) in 2024. Every cargo building, catering kitchen, hangar, and cooling tower runs through RP assemblies.
Authorities: AWWA M14 5th ed., USC FCCCHR, EPA CCC Manual, H&S Code § 116800.
Cities we serve in San Mateo County
Redwood City (county seat)
Oracle Redwood Shores (~6,500 employees, 60 acres, six towers) and Stanford Health Care Redwood City anchor commercial RP load. Redwood City runs its own independent cross-connection program rather than SMCEHS.
San Mateo
County's second-largest city. Mills-Peninsula (Sutter) at 1501 Trousdale is the anchor hospital; PlayStation / Sony Interactive Entertainment and Visa Foster City-adjacent operations drive additional commercial RP volume.
South San Francisco
The 'Birthplace of Biotech.' Genentech operates a 207-acre campus with ~15,000 workers, 1.7M sq ft of lab and 2.4M sq ft of office. SSF hosts 200+ biotech companies — an unusually dense high-hazard RP cluster.
Daly City, Colma, Brisbane
Daly City served by SMCEHS program (Seton Medical Center is the anchor hospital). Colma, with ~1,800 residents but ~1.5M interred, carries extensive cemetery irrigation backflow volume. Brisbane's Sierra Point and Baylands tech/office parks drive commercial DC/RP.
Foster City
Estero MID is the city's water provider. Gilead Sciences' 73-acre Foster City HQ plus a planned 800,000 sq ft expansion and 180,000 sq ft PDM center drives very significant process-water RP volume. Visa's 900 Metro Center Blvd campus adds commercial-RP load.
Menlo Park & Atherton
Meta (Facebook) HQ at 1 Meta Way occupies 30 buildings across 250+ bayside acres. Atherton and Portola Valley are on Cal Water Bear Gulch; mostly residential DC/PVB.
Burlingame, San Bruno, Millbrae
Mid-Peninsula commuter cities. SFO cargo, catering, and cooling-tower load falls in San Bruno / Burlingame; YouTube / Google at 901 Cherry Ave (San Bruno) is another headline commercial account.
Half Moon Bay, Pacifica, Moss Beach
Coastside County Water District, NCCWD, and Montara W&SD. CCWD prohibits Type II DCDA/RPDA within its service area. Oceanside hospitality and small ag/nursery drive commercial RP volume.
East Palo Alto
Served by Veolia under city contract + O'Connor Tract Co-op + Palo Alto Park Mutual. Mixed residential / institutional, with Stanford and Menlo Park campuses at the borders.
Belmont, San Carlos, Hillsborough, Woodside
Mid-Peninsula / Town of Hillsborough / Cal Water Bear Gulch. Residential DC/PVB dominates, with commercial RP at Peninsula medical and retail centers.
Our credentials
California
CCL #1062017
Active contractor state license.
Backflow tester
AWWA Backflow Tester Cert. #15112
AWWA-certified tester.
Specialist
AWWA Specialist Cert. #03373
Cross-Connection Control Specialist.
Family-owned
Jesse Cuevas
Owner and lead tester.
Jesse Cuevas has 13+ years in backflow prevention, installation, testing, and repair, including biotech process-water and commercial cooling-tower programs. We file directly under SMCEHS, Cal Water, Redwood City, CCWD, NCCWD, MPWD, MWSD, and Menlo Park channels. Field work is not sub-contracted.
Frequently asked questions
How often is backflow testing required in San Mateo County?
Every purveyor in San Mateo County requires an annual test. Most retail purveyors operate under a consolidated program administered by SMC Environmental Health Services under San Mateo County Code Chapter 4.72, §4.72.070, aligned with the CA SWRCB CCCPH.
Which water purveyors in San Mateo County require annual testing?
Cal Water Bear Gulch / Mid-Peninsula / South San Francisco districts (CPUC Tariff Rule 16), City of Redwood City, City of San Mateo (SMCEHS-administered), City of Daly City, City of Burlingame (MC 15.04.050), City of San Bruno, City of Millbrae (MC Ch. 8.10), Coastside County Water District, North Coast County Water District (Ord. 63-2025), Mid-Peninsula Water District, Town of Hillsborough, Estero MID (Foster City), Westborough WD, Brisbane Water / GVMID, Montara Water & Sanitary District, Menlo Park (MC Ch. 7.28), and Palo Alto Park Mutual all require annual testing.
What happens if my device fails the test?
We explain the failure on site, quote the repair (commonly a rubber kit, check, or relief valve), and schedule the retest. We avoid starting work without your approval. Under SMC Ordinance §4.72.070, failure to test can result in fines of up to $500 per day.
Who is legally allowed to test backflow devices in San Mateo County?
Only a backflow prevention assembly tester certified by AWWA or USC FCCCHR and listed on the applicable jurisdiction's approved tester roster. SMC Environmental Health maintains a county-specific Approved Backflow Tester List; Cal Water and Redwood City publish their own. Our lead specialist holds AWWA Backflow Tester Cert. #15112 and AWWA Specialist Cert. #03373; the company carries CCL #1062017.
Do Genentech, Gilead, and biotech-corridor campuses need backflow testing?
Yes. South San Francisco's biotech cluster (Genentech, BioMarin, Nektar, Exelixis) and Foster City's (Gilead, Visa) operate extensive RP-assembly programs on process water, CIP, boiler feed, cooling towers, and fire lines. Annual testing is required on every installed device.
Does SFO International Airport need backflow testing?
SFO is located in San Mateo County (not in San Francisco proper) and runs commercial-grade RP assemblies on cooling towers, cargo cold-chain, catering kitchens, fire systems, and hangar infrastructure. Annual testing is required under the applicable San Mateo County or city program.
Annual deadlines in San Mateo County are enforced under SMC § 4.72.070, CPUC Tariff Rule 16, or each district’s program. Non-compliance can result in fines of up to $500 per day.
Mon – Sat, 7:30 AM to 5:00 PM. Emergency response available.
Sources and authorities cited on this page
California state authority. CA SWRCB CCCPH, CA H&S Code § 116800.
Federal + standards. EPA CCC Manual, AWWA M14 5th ed., USC FCCCHR.
San Mateo County purveyors. SMC CCC Program, Cal Water CCC, Redwood City, Burlingame MC 15.04.050, Millbrae Ch. 8.10, CCWD, NCCWD Ord. 63-2025, Menlo Park Ch. 7.28.