Total Trihalomethanes (TTHM)
Unresolved Total Trihalomethanes Rule violation cited in 2022 (total trihalomethanes (tthm)).
PWSID CA3600399 · GroundwaterPrivate
106 people served. No health-based SDWIS violations recorded in the past 5 years. 7 remain unresolved. Last cited 4 years ago.
Unresolved Total Trihalomethanes Rule violation cited in 2022 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (total trihalomethanes (tthm)).
Unresolved Total Trihalomethanes Rule violation cited in 2022 (haloacetic acids (haa5)).
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; 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
San Juan Capistrano, California (Census place; block-group disparity scores aggregated by centroid containment): a service population of 35,099. Local disparity score for pm2.5 (fine particulate) sits moderately above the reference (113). Why we surface this →
Low-income
People of color
Under age 5
Over age 64
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 113 | moderately above the reference |
| Ozone | 98 | near the reference |
| Nitrogen dioxide (NO₂) | 68 | below the reference |
| Diesel particulate | 88 | below the reference |
| Toxic releases (RSEI) | 37 | well below the reference |
| Traffic proximity | 108 | near the reference |
| Lead-paint risk (pre-1960 housing) | 21 | well below the reference |
| Superfund site proximity | 53 | below the reference |
| RMP-facility proximity | 0 | well below the reference |
| Hazardous-waste site proximity | 102 | near the reference |
| Underground storage tanks | 0 | well below the reference |
| NPDES wastewater proximity | 96 | near 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 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.