Thallium
Unresolved Lead and Copper Rule violation cited in 2025 (thallium).
PWSID OK2003704 · GroundwaterMunicipal
2,058 people served. 2 health-based SDWIS violations recorded in the past 5 years. 8 remain unresolved. Last cited 1 year ago.
Unresolved Lead and Copper Rule violation cited in 2025 (thallium).
Unresolved Lead and Copper Rule violation cited in 2021 (contaminant 1064).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2021 (contaminant 5000).
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2021 (contaminant 5000).
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.
Failure to monitor as scheduled
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Maximum contaminant level exceeded; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; 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; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Maximum contaminant level exceeded; returned to compliance
Hennessey, Oklahoma (Census place; block-group disparity scores aggregated by centroid containment): a service population of 2,669. Local disparity score for pm2.5 (fine particulate) sits near the reference (108). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 108 | near the reference |
| Ozone | 123 | moderately above the reference |
| Nitrogen dioxide (NO₂) | 61 | below the reference |
| Diesel particulate | 23 | well below the reference |
| Toxic releases (RSEI) | 21 | well below the reference |
| Traffic proximity | 14 | well below the reference |
| Lead-paint risk (pre-1960 housing) | 75 | below the reference |
| Superfund site proximity | 0 | well below the reference |
| RMP-facility proximity | 126 | moderately above the reference |
| Hazardous-waste site proximity | 0 | well below the reference |
| Underground storage tanks | 75 | below the reference |
| NPDES wastewater proximity | 0 | well below the reference |
| Drinking-water non-compliance | 119 | moderately above 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.