No health-based violations on EPA record since 2016.
Serves about 10,108 people (3,108 connections) with groundwater from its own wells, and buys water from Yucaipa Valley Water District.
From EPA's record for CA3310017. PurityMap is independent of South Mesa WC.
Are you this utility? Correct this listing →
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 January 2023 to September 2023.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Perfluorohexanesulfonic acid (PFHxS) | 3.5 ng/L | 10 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorobutanesulfonic acid (PFBS) | 4.7 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Within the referenced health-based guidance value | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorohexanoic acid (PFHxA) | 6.8 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Within a historical reference; current applicability unverified | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoropentanoic acid (PFPeA) | 8.9 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| 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 | 2023-01-09 to 2023-07-12 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-07-12 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-07-12 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-07-12 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-07-12 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2023-01-09 to 2023-09-20 | UCMR5 Analytical Results: SOUTH MESA WC (CA3310017) |
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure
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 →South Mesa WC's phone number on EPA record is 909-795-2401. Its mailing address is P.O. BOX 458, 391 WEST AVE. L, CALIMESA, CA 92320.
According to EPA's record, South Mesa WC uses groundwater from its own wells, and buys water from Yucaipa Valley Water District.
No health-based violations on EPA record since 2016. The record comes from EPA's SDWIS compliance database.
Lead was not detected at the 90th percentile of tap samples in South Mesa WC's latest lead and copper round, which ended in December 2025. The federal action level is 15 µg/L.
PurityMap has no verified website for South Mesa WC. Its phone number on EPA record is 909-795-2401. Its mailing address on EPA record is P.O. BOX 458, 391 WEST AVE. L, CALIMESA, CA 92320. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.