California — 12th District
119th Congress · 233 ZIP codes · Avg score 71/100 · Grade B · Updated 2026-06-03
Data: EPA SDWIS / Census 119th Congress Last verified: 2026-06-03
Top Contaminants
ZIP Codes in This District
100 ZIP codes tracked in California's 12th District. Showing top 50 by safety score.
| # | ZIP Code | City | Safety Score | Grade | Violations |
|---|---|---|---|---|---|
| 1 | 94540 | Hayward | 83 | B | 0 |
| 2 | 94542 | Hayward | 83 | B | 0 |
| 3 | 94543 | Hayward | 83 | B | 0 |
| 4 | 94545 | Hayward | 83 | B | 0 |
| 5 | 94550 | Livermore | 83 | B | 0 |
| 6 | 94551 | Livermore | 83 | B | 0 |
| 7 | 94557 | Hayward | 83 | B | 0 |
| 8 | 94604 | Oakland | 83 | B | 0 |
| 9 | 94606 | Oakland | 83 | B | 0 |
| 10 | 94607 | Oakland | 83 | B | 0 |
| 11 | 94609 | Oakland | 83 | B | 0 |
| 12 | 94612 | Oakland | 83 | B | 0 |
| 13 | 94613 | Oakland | 83 | B | 0 |
| 14 | 94614 | Oakland | 83 | B | 0 |
| 15 | 94615 | Oakland | 83 | B | 0 |
| 16 | 94617 | Oakland | 83 | B | 0 |
| 17 | 94622 | Oakland | 83 | B | 0 |
| 18 | 94623 | Oakland | 83 | B | 0 |
| 19 | 94624 | Oakland | 83 | B | 0 |
| 20 | 94649 | Oakland | 83 | B | 0 |
| 21 | 94659 | Oakland | 83 | B | 0 |
| 22 | 94660 | Oakland | 83 | B | 0 |
| 23 | 94661 | Oakland | 83 | B | 0 |
| 24 | 94666 | Oakland | 83 | B | 0 |
| 25 | 94011 | Burlingame | 80 | B | 0 |
| 26 | 94552 | Castro Valley | 79 | B | 2 (1 health) |
| 27 | 95111 | San Jose | 79 | B | 4 (4 health) |
| 28 | 95113 | San Jose | 79 | B | 4 (4 health) |
| 29 | 95117 | San Jose | 79 | B | 4 (4 health) |
| 30 | 95118 | San Jose | 79 | B | 4 (4 health) |
| 31 | 95121 | San Jose | 79 | B | 4 (4 health) |
| 32 | 95123 | San Jose | 79 | B | 4 (4 health) |
| 33 | 95124 | San Jose | 79 | B | 4 (4 health) |
| 34 | 95126 | San Jose | 79 | B | 4 (4 health) |
| 35 | 95129 | San Jose | 79 | B | 4 (4 health) |
| 36 | 95131 | San Jose | 79 | B | 4 (4 health) |
| 37 | 95133 | San Jose | 79 | B | 4 (4 health) |
| 38 | 95134 | San Jose | 79 | B | 4 (4 health) |
| 39 | 95135 | San Jose | 79 | B | 4 (4 health) |
| 40 | 95136 | San Jose | 79 | B | 4 (4 health) |
| 41 | 95138 | San Jose | 79 | B | 4 (4 health) |
| 42 | 95153 | San Jose | 79 | B | 4 (4 health) |
| 43 | 95158 | San Jose | 79 | B | 4 (4 health) |
| 44 | 94536 | Fremont | 78 | B | 18 (1 health) |
| 45 | 94538 | Fremont | 78 | B | 18 (1 health) |
| 46 | 94539 | Fremont | 78 | B | 18 (1 health) |
| 47 | 94541 | Hayward | 78 | B | 0 |
| 48 | 94544 | Hayward | 78 | B | 0 |
| 49 | 94555 | Fremont | 78 | B | 18 (1 health) |
| 50 | 94601 | Oakland | 78 | B | 0 |
Overview
California's 12th District serving an estimated 392,568,271 residents encompasses 233 ZIP codes tracked by ZipCheckup. The district's average Home Safety Score is B (71/100).
530 EPA violations have been recorded across this district's water systems. 339 are health-based violations. About 65% of tracked ZIP codes have at least one violation.
Top Contaminants
The most frequently cited water quality issues in this district:
- E. coli — 228 violations
- Stage 2 DBP Rule — 222 violations
- Stage 1 DBP Rule — 80 violations
Housing Context
Homes in this district were built on average around 1968 (~58 years old). Older homes may have lead pipes or solder — consider a water filter if your home predates 1986.
Data Sources
- Water quality violations: EPA Safe Drinking Water Information System (SDWIS)
- Congressional district boundaries: U.S. Census Bureau, 119th Congress
- Housing age: U.S. Census Bureau American Community Survey
Updated daily. Data covers 233 ZIP codes in California's 12th District.