Is San Dimas, CA Tap Water Safe to Drink?
San Dimas tap water meets federal Safe Drinking Water Act standards but 1 of 1 ZIP code show detections above EPA health guidelines, primarily for lithium. A certified filter is recommended for households that want an additional layer of protection.
Where Does San Dimas Get Its Water?
Water in San Dimas, CA is provided by 1 public water system: GSWC-SAN DIMAS.
How Is San Dimas Tap Water Treated?
Treated water is disinfected using calcium hypochlorite and free chlorine.
What's in San Dimas Tap Water?
The following contaminants were detected most frequently in San Dimas public water systems. 1 of 1 ZIP codes showed detections above EPA health guidelines.
| Contaminant | Peak detected | EPA guideline | ZIPs detected | Status |
|---|---|---|---|---|
| lithium | 57 µg/L | 10 µg/L | 1 ZIP | Above guideline |
| PFTrDA | 0.007 µg/L | — | 0 ZIPs | Within guideline |
| HFPO-DA | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| PFBA | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 6:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
Health Risk Profile for San Dimas
Based on EPA monitoring data, 1 of 1 ZIP codes in San Dimas have recorded detections above EPA health guidelines. Sensitive populations such as infants, pregnant individuals, and those with weakened immune systems may benefit from an additional layer of protection such as a certified point-of-use filter.
Best Broad-Spectrum Filters for This Water Profile
This city profile includes PFAS detections, chlorine disinfection, and other dissolved contaminants. Reverse osmosis (RO) systems certified under NSF/ANSI 58 provide broad reduction coverage; for PFAS specifically, confirm NSF/ANSI P473 or equivalent PFAS reduction certification.
8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.
See recommendations matched to your exact address: choose your ZIP code below.
Frequently Asked Questions about San Dimas Tap Water
Is San Dimas tap water safe to drink?
San Dimas tap water meets Safe Drinking Water Act requirements but 1 of 1 ZIP codes show contaminant levels above EPA health-based guidelines. A certified point-of-use filter adds an extra layer of protection.
What contaminants are in San Dimas tap water?
The most commonly detected contaminants in San Dimas water systems include: lithium, PFTrDA, HFPO-DA. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does San Dimas get its drinking water?
San Dimas receives water from one public water system, including GSWC-SAN DIMAS.
Do I need a water filter in San Dimas?
If your ZIP code is among those with detections above EPA health guidelines, choose a filter certified for the specific contaminants shown in your ZIP report. Reverse osmosis is generally the broadest option for PFAS, lithium, and many other dissolved contaminants.
How often is San Dimas tap water tested?
Public water systems in San Dimas are required by the EPA to test for regulated contaminants on schedules ranging from daily (for microbials and disinfectants) to annual or triennial (for many chemical contaminants). Results are published in annual Consumer Confidence Reports (CCRs). The data on this page reflects the most recent available EPA monitoring results, with the latest sample date of 2025-02-26.
Tap water reports by ZIP in San Dimas
- 91773 - San Dimas tap water report Higher concern
Water utilities serving San Dimas, CA
Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.
- GSWC-SAN DIMASAction advised
- THREE VALLEYS MWDNo recent federal sampling
Also covers / overlaps with
- East San Gabriel Valley CCD, CA · Township
- South Antelope Valley CCD, CA · Township