No open health-based violations on EPA record in the last 10 years.
Serves about 6,939 people (2,313 connections) with surface water from its own intake.
From EPA's record for TX2140016. PurityMap is independent of Rio WSC.
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1 health-based violation in the last 10 years, from EPA's SDWIS compliance database.
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| From October 2024 | Lead and copper rule revisions | – | – | Resolved |
EPA required this system to test for 30 unregulated and emerging contaminants, from January 2023 to January 2024.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Lithium | 43.7 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Above the referenced health-based guidance value | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorobutanoic acid (PFBA) | 7.7 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2023-01-23 to 2024-01-31 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| 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 | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-23 to 2023-10-18 | UCMR5 Analytical Results: RIO WSC (TX2140016) |
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 →Rio WSC's phone number on EPA record is 956-487-2085. Its mailing address is 42 N SUNTEX RD, RIO GRANDE CITY, TX 78582-6229.
According to EPA's record, Rio WSC uses surface water from its own intake.
EPA's record shows 1 health-based violation for Rio WSC in the 10 years to July 9, 2026. No open health-based violations on EPA record in the last 10 years. EPA also lists 31 missed or late tests or reports in 10 years. The record comes from EPA's SDWIS compliance database.
Lead was not detected at the 90th percentile of tap samples in Rio WSC's latest lead and copper round, which ended in December 2024. The federal action level is 15 µg/L.
PurityMap has no verified website for Rio WSC. Its phone number on EPA record is 956-487-2085. Its mailing address on EPA record is 42 N SUNTEX RD, RIO GRANDE CITY, TX 78582-6229. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.