Arsenic
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (arsenic).
PWSID WA5310761 · GroundwaterPrivate
97 people served. 5 health-based SDWIS violations recorded in the past 5 years. 32 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 2024 (arsenic).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2024 (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.
OTHER; returned to compliance
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded
Maximum contaminant level exceeded
OTHER; returned to compliance
OTHER; returned to compliance
Monitoring failure; returned to compliance
Monitoring failure; returned to compliance
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Failure to monitor as scheduled
Pasco, Washington (Census place; block-group disparity scores aggregated by centroid containment): a service population of 77,274. Local disparity score for pm2.5 (fine particulate) sits well above the reference burden (185). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 185 | well above the reference burden |
| Ozone | 96 | near the reference |
| Nitrogen dioxide (NO₂) | 120 | moderately above the reference |
| Diesel particulate | 127 | moderately above the reference |
| Toxic releases (RSEI) | 57 | below the reference |
| Traffic proximity | 95 | near the reference |
| Lead-paint risk (pre-1960 housing) | 79 | below the reference |
| Superfund site proximity | 134 | moderately above the reference |
| RMP-facility proximity | 179 | well above the reference burden |
| Hazardous-waste site proximity | 97 | near the reference |
| Underground storage tanks | 92 | near the reference |
| NPDES wastewater proximity | 70 | below 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 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.