San Mateo Water Quality Report
15 cities ranked · Average grade: A- · California
Avg Score
89.3
Cities Ranked
15
Health Violations
14
PFAS Detected
3
89.3
County avg score
15
Cities ranked
93%
A or B grade
0%
D or F grade
14
Health violations
3
PFAS detected
Grade Distribution
How San Mateo cities scored
A
13
87%
Excellent
B
1
7%
Good
C
1
7%
Fair
D
0
0%
Poor
F
0
0%
Failing
Comparison
County vs California average
▲ 12.8 pts above state average
City Map
Water quality across San Mateo
Each dot is a city, colored by grade. Click any city to view its full report.
Highlights
Top & bottom cities in San Mateo
County context
0
lbs/yr to surface water · top 10 TRI facilities
Industrial pollution
Top industrial polluters in San Mateo
Industrial polluters nearby
Facilities reporting the most surface-water releases in San Mateo, 2023.
Total reported releases to surface water: 0 lbs
| Facility | Top chemical | To surface water (lbs/yr) |
|---|---|---|
GRANITE ROCK CO REDWOOD CITY REDWOOD CITY, CA94063 | Barium | 0 |
GARRATT-CALLAHAN CO BURLINGAME BURLINGAME, CA94010 | — | — |
US DOE SLAC NATIONAL ACCELERATOR LABORATORY MENLO PARK, CA94025 | — | — |
CSBIO MENLO PARK, CA94025 | — | — |
UNIVAR SOLUTIONS USA REDWOOD CITY, CA94063 | — | — |
+ 4 more facilities
Source: EPA Toxic Release Inventory (TRI) 2023
Full Rankings
All 15 cities in San Mateo
| # | City | Grade | Score | Score | Population | Violations | Issues |
|---|---|---|---|---|---|---|---|
| 1 | Belmont | A+ | 98.2 | 31K | 3 | Health | |
| 2 | Foster City | A+ | 97.9 | 37K | 5 | Health | |
| 3 | San Bruno | A+ | 95.3 | 41K | 1 | ||
| 4 | South San Francisco | A | 94.8 | 14K | 10 | Health Unresolved | |
| 5 | Pacifica | A | 93.2 | 39K | 3 | Health Unresolved | |
| 6 | Half Moon Bay | A | 93 | 19K | 15 | Health Unresolved | |
| 7 | East Palo Alto | A | 92.7 | 32K | 19 | Health Unresolved | |
| 8 | Daly City | A | 91.9 | 105K | 5 | Health Unresolved | |
| 9 | Hillsborough | A | 91.2 | 12K | 18 | Health Unresolved | |
| 10 | Montara | A- | 89.8 | 6K | 5 | Health Unresolved | |
| 11 | Menlo Park | A- | 89.2 | 23K | 11 | Health Unresolved | |
| 12 | Brisbane | A- | 87.5 | 5K | 15 | Health PFAS Unresolved | |
| 13 | Millbrae | A- | 86.9 | 23K | 11 | Health Unresolved | |
| 14 | Redwood City | B+ | 80.5 | 94K | 85 | Health Unresolved | |
| 15 | La Honda | C- | 56.8 | 1K | 143 | Health Lead Unresolved |