Drinking water quality · 2023
· Verified
· PWSID CA1910212
What's in Gswc-south Arcadia — San Dimas, Ca, CA tap water
1 contaminant in Gswc-south Arcadia — San Dimas, Ca, CA's water sat at or above a federal limit, led by PFOS at 1.4x the limit.
- !1 contaminant at or above a federal limit — worst is PFOS at 1.4x
- !11 of 27 core regulated contaminants reported — 16 never appear in this report
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −17 contaminants at or above a federal limit
- −0 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −13 core regulated contaminants never reported (11/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- PFOS1.4× the federal limit5.4 ng/L · limit 4 ng/L
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
Higher than 55% of CA systems that report it · higher than 65% of U.S. systems
+17 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| Chlorine | 1.5 mg/L | 4 mg/L |
| Copper | 0.28 mg/L | 1.3 mg/L |
| Nitrate | 1.6 mg/L | 10 mg/L |
| Fluoride | 0.6 mg/L | 4 mg/L |
| TTHM | 5.3 ug/L | 80 ug/L |
| HAA5 | Not detected ug/L | 60 ug/L |
| Perchlorate | Not detected ug/L | — |
| Aluminum | Not detected mg/L | — |
| Chromium, Hexavalent | 4.2 ug/L | — |
| Chromium, Total | Not detected ug/L | 100 ug/L |
| Lead | 0.0 mg/L | 0.015 mg/L |
| Pce | Not detected ug/L | 5 ug/L |
| Perfluorohexanesulfonic acid | Not detected ng/L | 10 ng/L |
| PFBA | 1.2 ng/L | — |
| PFOA | Not detected ng/L | 4 ng/L |
| Gross Alpha | Not detected pCi/L | 15 pCi/L |
| Uranium | 1.8 pCi/L | 20 pCi/L |
What this report doesn't tell you
16 of the 27 contaminants a community water system normally reports do not appear anywhere in Gswc-south Arcadia — San Dimas, Ca, CA's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.