No health-based violations on EPA record since 2016.
Serves about 3,500 people (1,228 connections) with surface water from its own intake, and buys water from San Francisco Regional Water System.
From EPA's record for CA3810700. PurityMap is independent of Presidio of San Francisco.
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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 |
|---|---|---|---|---|---|
| Perfluorooctanoic acid (PFOA) | 4 ng/L | 4.0 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorohexanesulfonic acid (PFHxS) | 4.6 ng/L | 10 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorobutanesulfonic acid (PFBS) | 4.9 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 | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorohexanoic acid (PFHxA) | 6.8 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Within a historical reference; current applicability unverified | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorobutanoic acid (PFBA) | 6.2 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluoroheptanoic acid (PFHpA) | 3.1 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluoropentanoic acid (PFPeA) | 8.9 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| 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 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-11 to 2025-09-15 | UCMR5 Analytical Results: PRESIDIO OF SAN FRANCISCO (CA3810700) |
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 →Presidio of San Francisco's phone number on EPA record is 415-561-4134. Its mailing address is PO BOX 29052, SAN FRANCISCO, CA 94129-0052.
According to EPA's record, Presidio of San Francisco uses surface water from its own intake, and buys water from San Francisco Regional Water System.
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 Presidio of San Francisco'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 Presidio of San Francisco. Its phone number on EPA record is 415-561-4134. Its mailing address on EPA record is PO BOX 29052, SAN FRANCISCO, CA 94129-0052. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.