Arsenic
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (arsenic).
PWSID CA1502744 · GroundwaterPrivate
39 people served. 4 health-based SDWIS violations recorded in the past 5 years. 4 remain unresolved. Last cited 1 year ago.
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (arsenic).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (arsenic).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2020 (arsenic).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2020 (arsenic).
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.
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Rosamond, California (Census place; block-group disparity scores aggregated by centroid containment): a service population of 20,654. Local disparity score for pm2.5 (fine particulate) sits moderately above the reference (144). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 144 | moderately above the reference |
| Ozone | 180 | well above the reference burden |
| Nitrogen dioxide (NO₂) | 136 | moderately above the reference |
| Diesel particulate | 67 | below the reference |
| Toxic releases (RSEI) | 100 | near the reference |
| Traffic proximity | 65 | below the reference |
| Lead-paint risk (pre-1960 housing) | 43 | well below the reference |
| Superfund site proximity | 145 | moderately above the reference |
| RMP-facility proximity | 96 | near the reference |
| Hazardous-waste site proximity | 13 | well below the reference |
| Underground storage tanks | 0 | well below the reference |
| NPDES wastewater proximity | 0 | well below the reference |
| Drinking-water non-compliance | 42 | 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 2020-01-01 → 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.