Harris County tap water
3 of 255 water systems serving Harris County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 701 community water systems list this county as served; 242 serve 3,300+ people with full PFAS testing.
- 97 had a health-based violation since 2021-10-26.
Largest systems serving this county
| System | Source | People served (whole system) | PFAS above a 2024 level? | Violations since 2021-10-26 |
|---|---|---|---|---|
| City of Houston | Surface water | 2,970,543 | No | 1 |
| City of Pasadena | Purchased surface water | 152,000 | No | 0 |
| Clear Lake City Water Authority | Purchased surface water | 89,702 | Yes | 0 |
| City of Baytown | Purchased surface water | 86,004 | Yes | 0 |
| City of Houston Ud 5 - Kingwood | Groundwater | 80,073 | No | 0 |
| Harris County Mud 165 | Purchased surface water | 40,503 | No | 0 |
| City of LA Porte | Purchased surface water | 36,569 | No | 0 |
| City of Deer Park | Purchased surface water | 34,495 | No | 0 |
| Northwest Harris County Mud 5 | Purchased surface water | 25,425 | No | 0 |
| City of Katy | Groundwater | 25,253 | No | 0 |
| Bridgestone Mud | Purchased surface water | 24,528 | No | 0 |
| Timber Lane Utility District | Groundwater | 24,507 | No | 0 |
Which one is yours? A county usually has several utilities. Your bill or your utility's annual water-quality report names yours. Population is for the whole system, which can cross county lines.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.