Contaminant 0200
Unresolved Surface Water Treatment Rule violation cited in 2025 (contaminant 0200).
PWSID CA5510007 · Surface waterPrivate
1,295 people served. 10 health-based SDWIS violations recorded in the past 5 years. 6 remain unresolved. Last cited 1 year ago.
Unresolved Surface Water Treatment Rule violation cited in 2025 (contaminant 0200).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (haloacetic acids (haa5)).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (haloacetic acids (haa5)).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (haloacetic acids (haa5)).
Health-based violations exceed an MCL or treatment-technique standard. Monitoring violations are reporting failures with no measured exceedance — they tell you the system isn't fully transparent, not that the water is unsafe today.
Treatment technique violation
Treatment technique violation; returned to compliance
Maximum contaminant level exceeded
Maximum contaminant level exceeded; returned to compliance
Maximum contaminant level exceeded
Maximum contaminant level exceeded; returned to compliance
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded; returned to compliance
Maximum contaminant level exceeded
Chico, California (Census place; block-group disparity scores aggregated by centroid containment): a service population of 102,790. Local disparity score for pm2.5 (fine particulate) sits moderately above the reference (139). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 139 | moderately above the reference |
| Ozone | 124 | moderately above the reference |
| Nitrogen dioxide (NO₂) | 81 | below the reference |
| Diesel particulate | 85 | below the reference |
| Toxic releases (RSEI) | 7 | well below the reference |
| Traffic proximity | 86 | below the reference |
| Lead-paint risk (pre-1960 housing) | 63 | below the reference |
| Superfund site proximity | 0 | well below the reference |
| RMP-facility proximity | 49 | well below the reference |
| Hazardous-waste site proximity | 98 | near the reference |
| Underground storage tanks | 0 | well below the reference |
| NPDES wastewater proximity | 93 | near the reference |
| Drinking-water non-compliance | 0 | well below the reference |
Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror).
Source. EPA Safe Drinking Water Information System · retrieved 2026-05-07. Reporting period 2022-01-01 → 2026-05-07.
What this is not. SDWIS records compliance against federal MCLs — not a direct readout of tap-water concentrations. Active health-based violations are not the same as a current crisis; we link to the EPA record so you can verify return-to-compliance status before forming a conclusion.