San Mateo County, California — Property Hazard, Flood Zone, Soil, Water & EPA Guide
What Are the Flood, Soil Foundation & EPA Risks in San Mateo County, CA?
In San Mateo County, California, public U.S. EPA records track 17,259 regulated facilities (#9 of 136 in California), including 17 (0.1%) High-Risk sites and $11,392,771 in federal penalties. Countywide due diligence also covers 62 Safe Drinking Water (SDWIS) facilities, 294 Clean Water NPDES permits, 4 FEMA Federal Disaster Declarations (4 flood/storm), USDA Soil Foundation Shrink-Swell (MODERATE signal), and EPA Zone 2 — Moderate Potential (2.0 – 4.0 pCi/L).
San Mateo County, CA 6-in-1 Flood, Soil Foundation, Tap Water & Radon Signals
🔒 Parcel-Level Soil LEP %, Water Table Depth & Flood Zone Require Street Address Scan📊 San Mateo County, CA Statistical Risk Graphs & Multi-Hazard Telemetry
SOURCE: EPA ECHO • USDA SSURGO • FEMA NRI • USGS (November 03, 2026)Municipalities in San Mateo County
ZIP Codes in San Mateo County
Top EPA Regulated Facilities in San Mateo County, CA
100% of High-Risk & penalized facilities have facility names, street names, and dockets redacted (3 Low-Risk compliant records shown as Free Previews).
| Facility Name / Hazard Type | Sector Location (Street Redacted) | Risk Tier & Score | Compliance Status | Enforcement / Unlock |
|---|---|---|---|---|
| 🔒 Locked High-Risk EPA Enforcement Record #1 | 🔒 Exact Street & Parcel Redacted • HALF MOON BAY, CA (ZIP 94019 Sector) | HIGH (94/100) | Significant Violation (12 qtrs NC) | 🔒 $10,000+ Federal Fine • Unlock → |
| 🔒 Locked High-Risk EPA Enforcement Record #2 | 🔒 Exact Street & Parcel Redacted • SAN FRANCISCO INTNL AIRPORT, CA (ZIP 94128 Sector) | HIGH (78/100) | Significant Violation (12 qtrs NC) | 🔒 $10,000+ Federal Fine • Unlock → |
| 🔒 Locked High-Risk EPA Enforcement Record #3 | 🔒 Exact Street & Parcel Redacted • COLMA, CA (ZIP 94014 Sector) | HIGH (76/100) | Significant Violation (12 qtrs NC) | 🔒 12 Qtrs Non-Compliance • Unlock → |
| 🔒 Locked High-Risk EPA Enforcement Record #4 | 🔒 Exact Street & Parcel Redacted • SAN FRANCISCO INTNL AIRPORT, CA (ZIP 94128 Sector) | HIGH (69/100) | Significant Violation (12 qtrs NC) | 🔒 Federal Penalty on File • Unlock → |
| 🔒 Locked High-Risk EPA Enforcement Record #5 | 🔒 Exact Street & Parcel Redacted • SOUTH SAN FRANCISCO, CA (ZIP 94080 Sector) | HIGH (65/100) | Violation (3 qtrs NC) | 🔒 $100,000+ Federal Fine • Unlock → |
| 🔒 Locked High-Risk EPA Enforcement Record #6 | 🔒 Exact Street & Parcel Redacted • REDWOOD CITY, CA (ZIP 94063 Sector) | HIGH (64/100) | Significant Violation (12 qtrs NC) | 🔒 12 Qtrs Non-Compliance • Unlock → |
| 🔒 Locked Regulated EPA Enforcement Record #7 | 🔒 Exact Street & Parcel Redacted • REDWOOD CITY, CA (ZIP 94063 Sector) | MODERATE (57/100) | Resolved / Historical Non-Compliance (3 qtrs NC) | 🔒 $100,000+ Federal Fine • Unlock → |
| 🔒 Locked Regulated EPA Enforcement Record #8 | 🔒 Exact Street & Parcel Redacted • REDWOOD CITY, CA (ZIP 94063 Sector) | MODERATE (56/100) | Violation (12 qtrs NC) | 🔒 12 Qtrs Non-Compliance • Unlock → |
| HUDSON AUTOMOTIVE INC FREE PREVIEW (LOW RISK) | 186 SOUTH BLVD, SAN MATEO, CA 94402 | LOW (16/100) | No Violation Identified (0 qtrs NC) | $0 |
| MENLO COLLEGE FREE PREVIEW (LOW RISK) | , ATHERTON, CA 94027 | LOW (12/100) | Inactive (0 qtrs NC) | $0 |
| BJORN IMPORT LLC FREE PREVIEW (LOW RISK) | 275 SHORELINE DR STE 450, REDWOOD CITY, CA 94065 | LOW (11/100) | No Violation Identified (0 qtrs NC) | $0 |
| BUTANO CANYON MUTUAL FREE PREVIEW (LOW RISK) | , PESCADERO, CA 94060 | LOW (11/100) | No Violation Identified (0 qtrs NC) | $0 |
Frequently Asked Questions — San Mateo County, California Environmental Due Diligence
How many EPA-regulated environmental sites are in San Mateo County, California?
Public U.S. EPA records track 17,259 regulated facilities in San Mateo County, California (ranking #9 of 136 jurisdictions in CA). Of those, 17 (0.1%) are classified in the High-Risk tier due to significant enforcement or chemical release history, and 25 (0.1%) have active non-compliance quarters.
Which ZIP codes and cities in San Mateo County have the highest regulated facility density?
Within San Mateo County, the highest concentrations of EPA-tracked facilities are located in ZIP 94080 (S San Francisco, 2,403 sites), ZIP 94010 (Burlingame, 1,485 sites), ZIP 94070 (Atherton, 1,466 sites), spanning municipal corridors including San Mateo (2,632 sites), South San Francisco (2,189 sites), Redwood City (2,055 sites).
How many hazardous waste (RCRA) and toxic release (TRI) handlers operate in San Mateo County?
Across San Mateo County, 17,066 facilities (98.9% of regulated sites) are registered Resource Conservation and Recovery Act (RCRA) hazardous waste generators or handlers, and 0 industrial sites report toxic chemical releases to the EPA Toxics Release Inventory (TRI).
What is the EPA Radon Zone classification for San Mateo County, CA?
Geologic indoor air screening places San Mateo County in EPA Zone 2 — Moderate Potential (2.0 – 4.0 pCi/L). Counties in EPA Radon Zone 2 have a predicted average indoor radon level between 2.0 and 4.0 pCi/L. Testing basement or ground-floor living areas is recommended during home inspection.
How many drinking water systems (SDWIS), impaired water bodies, and FEMA flood disasters are recorded in San Mateo County, CA?
Federal records track 62 Safe Drinking Water (SDWIS) facilities, 294 Clean Water Act NPDES permits, and 36 impaired water dischargers in San Mateo County, alongside 4 historical FEMA federal disaster declarations (4 flood/storm events).
Does San Mateo County, CA have expansive clay soil or foundation risk?
USDA regional soil engineering screening for San Mateo County indicates a MODERATE shrink-swell risk signal and steel pipe corrosivity rated Low. Run a street address scan to unlock the exact parcel soil series, LEP %, and water table depth.