Total Trihalomethanes (TTHM)
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
PWSID LA1009014 · GroundwaterMunicipal
2,142 people served. 7 health-based SDWIS violations recorded in the past 5 years. 4 remain unresolved. Last cited 1 year ago.
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2024 (total trihalomethanes (tthm)).
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; returned to compliance
OTHER; returned to compliance
Maximum contaminant level exceeded
Treatment technique violation; returned to compliance
Treatment technique violation; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
Simmesport, Louisiana (Census place; block-group disparity scores aggregated by centroid containment): a service population of 1,308. Local disparity score for pm2.5 (fine particulate) sits below the reference (76). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 76 | below the reference |
| Ozone | 27 | well below the reference |
| Nitrogen dioxide (NO₂) | 76 | below the reference |
| Diesel particulate | 30 | well below the reference |
| Toxic releases (RSEI) | 8 | well below the reference |
| Traffic proximity | 0 | well below the reference |
| Lead-paint risk (pre-1960 housing) | 133 | moderately above the reference |
| Superfund site proximity | 0 | well below the reference |
| RMP-facility proximity | 0 | well below the reference |
| Hazardous-waste site proximity | 0 | well below the reference |
| Underground storage tanks | 111 | moderately above the reference |
| NPDES wastewater proximity | 38 | well below the reference |
| Drinking-water non-compliance | 247 | severely above the reference burden |
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.