Is Diamond Bar, CA Tap Water Safe to Drink?
Diamond Bar 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 Diamond Bar Get Its Water?
Water in Diamond Bar, CA is provided by 2 public water systems: WALNUT VALLEY WATER DISTRICT and WESTERN MWD.
How Is Diamond Bar Tap Water Treated?
Treated water is disinfected using free chlorine and calcium hypochlorite and chloramines and ozone. Treatment includes conventional treatment (coagulation, flocculation, and filtration) and post-ozone biofiltration.
What's in Diamond Bar Tap Water?
The following contaminants were detected most frequently in Diamond Bar public water systems. 1 of 1 ZIP codes showed detections above EPA health guidelines.
| Contaminant | Peak detected | EPA guideline | ZIPs detected | Status |
|---|---|---|---|---|
| lithium | 33.8 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 |
| 8:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 6:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
Health Risk Profile for Diamond Bar
Based on EPA monitoring data, 1 of 1 ZIP codes in Diamond Bar 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 Diamond Bar Tap Water
Is Diamond Bar tap water safe to drink?
Diamond Bar 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 Diamond Bar tap water?
The most commonly detected contaminants in Diamond Bar water systems include: lithium, PFTrDA, HFPO-DA. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does Diamond Bar get its drinking water?
Diamond Bar receives water from 2 public water systems, including WALNUT VALLEY WATER DISTRICT.
Do I need a water filter in Diamond Bar?
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 Diamond Bar tap water tested?
Public water systems in Diamond Bar 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 2024-11-19.
Tap water reports by ZIP in Diamond Bar
- 91765 - Diamond Bar tap water report Higher concern
Water utilities serving Diamond Bar, 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.
- WALNUT VALLEY WATER DISTRICTAction advised
- THREE VALLEYS MWDNo recent federal sampling
Also covers / overlaps with
- East San Gabriel Valley CCD, CA · Township