California — 35th District
119th Congress · 20 ZIP codes · Avg score 77/100 · Grade B · Updated 2026-07-19
Data: EPA SDWIS / Census 119th Congress Last verified: 2026-07-19
ZipCheckup tracks water safety for 20 ZIP codes in California's 35th District: the district earns a grade B (77/100). 23 EPA violations on record, 10 health-based.
Top Contaminants
ZIP Codes in This District
20 ZIP codes tracked in California's 35th District.
| # | ZIP Code | City | Safety Score | Grade | Violations |
|---|---|---|---|---|---|
| 1 | 91758 | Ontario | 83 | B | 0 |
| 2 | 91761 | Ontario | 83 | B | 0 |
| 3 | 91762 | Ontario | 83 | B | 0 |
| 4 | 91785 | Upland | 83 | B | 0 |
| 5 | 91786 | Upland | 83 | B | 0 |
| 6 | 91798 | Ontario | 83 | B | 0 |
| 7 | 91729 | Rancho Cucamonga | 82 | B | 3 |
| 8 | 91710 | Chino | 79 | B | 2 (1 health) |
| 9 | 91708 | Chino | 78 | B | 2 (1 health) |
| 10 | 91764 | Ontario | 78 | B | 0 |
| 11 | 91766 | Pomona | 78 | B | 4 (2 health) |
| 12 | 91768 | Pomona | 78 | B | 4 (2 health) |
| 13 | 91767 | Pomona | 77 | B | 4 (2 health) |
| 14 | 91769 | Pomona | 77 | B | 4 (2 health) |
| 15 | 92337 | Fontana | 75 | B | 0 |
| 16 | 91763 | Montclair | 72 | B | 0 |
| 17 | 92331 | Fontana | 72 | B | 0 |
| 18 | 92334 | Fontana | 72 | B | 0 |
| 19 | 92335 | Fontana | 70 | B | 0 |
| 20 | 91743 | Guasti | 53 | D | 0 |
Overview
California's 35th District encompasses 20 ZIP codes tracked by ZipCheckup. The district's average Home Safety Score is B (77/100).
23 EPA violations have been recorded across this district's water systems. 10 are health-based violations. About 35% of tracked ZIP codes have at least one violation.
Top Contaminants
The most frequently cited water quality issues in this district:
- Stage 2 DBP Rule - 8 violations
- Total Organic Carbon - 4 violations
- Haloacetic Acids (HAA5) - 4 violations
- Stage 1 DBP Rule - 3 violations
- Contaminant 0700 - 2 violations
Housing Context
Homes in this district were built on average around 1974 (~52 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 20 ZIP codes in California's 35th District.