Water report · not indexed
What is in the water at 91767
2 public water systems serve this ZIP code in the federal records. Everything below comes from EPA monitoring data, and everything missing is named.
GSWC - CLAREMONT
PWSID CA1910024 · CA · serves 39,730 people
PFAS and lithium
7 compounds detected at or above the reporting limit under EPA’s UCMR 5 monitoring, across 34 samples.
| Compound | Highest detected | Samples | Most recent |
|---|---|---|---|
| PFOA | 0.013 µg/L | 5 | 9/27/2023 |
| PFOS | 0.01 µg/L | 1 | 9/27/2023 |
| PFHxA | 0.0084 µg/L | 8 | 9/27/2023 |
| PFPeA | 0.0064 µg/L | 8 | 9/27/2023 |
| PFBS | 0.0051 µg/L | 5 | 6/4/2024 |
| PFHpA | 0.0046 µg/L | 4 | 9/27/2023 |
| PFHxS | 0.0037 µg/L | 3 | 3/19/2024 |
A detection is a measurement, not a violation and not a health finding. EPA states that UCMR 5 results do not indicate compliance or non-compliance with any limit.
Health-based violations
No open health-based violation on record. This covers MCL, treatment technique and MRDL violations in SDWIS that have not been returned to compliance. It excludes monitoring and reporting violations, which are the large majority nationally, so this is not “no violations”, and SDWIS completeness varies by state.
Hardness
No hardness measurement. Hardness is measured at environmental monitoring stations, and none fell inside this system’s service area. That is a gap in where monitoring happens, not a finding about the water.
POMONA - CITY, WATER DEPT.
PWSID CA1910126 · CA · serves 151,713 people
PFAS and lithium
7 compounds detected at or above the reporting limit under EPA’s UCMR 5 monitoring, across 13 samples.
| Compound | Highest detected | Samples | Most recent |
|---|---|---|---|
| lithium | 9.3 µg/L | 1 | 8/23/2023 |
| PFOS | 0.018 µg/L | 2 | 8/23/2023 |
| PFHxS | 0.0079 µg/L | 2 | 8/23/2023 |
| PFOA | 0.0071 µg/L | 2 | 8/23/2023 |
| PFPeA | 0.0044 µg/L | 2 | 8/23/2023 |
| PFHxA | 0.0041 µg/L | 2 | 8/23/2023 |
| PFBS | 0.0032 µg/L | 2 | 8/23/2023 |
A detection is a measurement, not a violation and not a health finding. EPA states that UCMR 5 results do not indicate compliance or non-compliance with any limit.
Health-based violations
No open health-based violation on record. This covers MCL, treatment technique and MRDL violations in SDWIS that have not been returned to compliance. It excludes monitoring and reporting violations, which are the large majority nationally, so this is not “no violations”, and SDWIS completeness varies by state.
Hardness
Too few readings to state a hardness. 3 station(s), 4 result(s). Below two stations and five results this page will not state a number: a median of two readings from one creek is not your water.
What this report cannot tell you
Every figure describes water at a sampling point: a treatment plant, an entry point to the distribution system, or a monitoring station. None of it describes water arriving at your tap. Plumbing between the two can add lead and copper, and if your home was built before 1986 a test kit tells you something no federal dataset can.
Sources: EPA UCMR 5 occurrence (final release, frozen July 2026) · EPA SDWIS health-based violations · USGS and state monitoring via the Water Quality Portal · EPA Public Water System Service Area Boundaries v3. Compiled 2026-09-01.