No health-based violations on EPA record since 2016.
Serves about 3,501 people (1,169 connections) with surface water bought from Harris County MUD 149 and West Harris County Regional Water Author.
From EPA's record for TX1012985. PurityMap is independent of Harris County MUD 257.
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No health-based violations in the last 10 years, from EPA's SDWIS compliance database.
EPA required this system to test for 30 unregulated and emerging contaminants, from March 2025 to September 2025.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Perfluorohexanoic acid (PFHxA) | 3.2 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Within a historical reference; current applicability unverified | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorobutanoic acid (PFBA) | 5.6 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoropentanoic acid (PFPeA) | 3.4 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Lithium | < 9 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-22 | UCMR5 Analytical Results: HARRIS COUNTY MUD 257 (TX1012985) |
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
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Screening: quick check, not lab-grade
Safe Home (EnviroTestKits)
Lead, read as one of three ranges: 0–4, 5–15 or 15+ ppb
Turnaround: 5 minutes
What it can't tell you: It shows a lead range, not an exact level, and tests nothing else unless you pay extra for the optional lab test.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638 · 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Get PurityMap updates about this water system.
Follow this water →Harris County MUD 257's phone number on EPA record is 713-623-4531. Its mailing address is 1300 POST OAK BLVD STE 2400, HOUSTON, TX 77056-3044.
According to EPA's record, Harris County MUD 257 uses surface water bought from Harris County MUD 149 and West Harris County Regional Water Author.
No health-based violations on EPA record since 2016. EPA also lists 1 missed or late test or report in 10 years. The record comes from EPA's SDWIS compliance database.
The 90th-percentile lead result in Harris County MUD 257's latest lead and copper round, which ended in December 2024, was 3 µg/L, below the federal action level of 15 µg/L.
PurityMap has no verified website for Harris County MUD 257. Its phone number on EPA record is 713-623-4531. Its mailing address on EPA record is 1300 POST OAK BLVD STE 2400, HOUSTON, TX 77056-3044. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.