Total Trihalomethanes (TTHM)
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
PWSID TX2120016 · GroundwaterMunicipal
5,532 people served. 3 health-based SDWIS violations recorded in the past 5 years. 2 remain unresolved. Last cited 1 year ago.
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
Unresolved Phase I/II/V Synthetic Organic Chemical Rules violation cited in 2025 (contaminant 7000).
Total Trihalomethanes Rule health-based violation cited in 2025 (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; returned to compliance
OTHER
Failure to monitor as scheduled; returned to compliance
OTHER; returned to compliance
OTHER; returned to compliance
OTHER; returned to compliance
Failure to monitor as scheduled; returned to compliance
Failure to monitor as scheduled; returned to compliance
OTHER; 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
OTHER; returned to compliance
OTHER; returned to compliance
Maximum contaminant level exceeded; returned to compliance
OTHER; returned to compliance
Tyler, Texas (Census place; block-group disparity scores aggregated by centroid containment): a service population of 106,440. Local disparity score for pm2.5 (fine particulate) sits near the reference (95). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 95 | near the reference |
| Ozone | 42 | well below the reference |
| Nitrogen dioxide (NO₂) | 96 | near the reference |
| Diesel particulate | 60 | below the reference |
| Toxic releases (RSEI) | 98 | near the reference |
| Traffic proximity | 72 | below the reference |
| Lead-paint risk (pre-1960 housing) | 89 | below the reference |
| Superfund site proximity | 0 | well below the reference |
| RMP-facility proximity | 140 | moderately above the reference |
| Hazardous-waste site proximity | 51 | below the reference |
| Underground storage tanks | 110 | near the reference |
| NPDES wastewater proximity | 56 | below the reference |
| Drinking-water non-compliance | 150 | well 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 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.