Los Angeles, California
| Contaminant | Detected | EPA limit | EWG guideline | Status |
|---|---|---|---|---|
| Chromium-6 (Hexavalent Chromium) | 0.28 ppb | — | 0.02 ppb | 14× EWG |
| Total Trihalomethanes (TTHMs) | 48.2 ppb | 80 ppb | 0.8 ppb | 60× EWG |
| Haloacetic Acids (HAA5) | 30.6 ppb | 60 ppb | 0.1 ppb | 306× EWG |
| Arsenic | 2.8 ppb | 10 ppb | 0.004 ppb | 700× EWG |
| PFAS (PFOA + PFOS) | 3.2 ppt | 4 ppt | 0.004 ppt | 800× EWG |
| Uranium | 2.1 µg/L | 30 µg/L | 0.43 µg/L | 5× EWG |
| Lead | 1.2 ppb | 15 ppb | 0.5 ppb | 2× EWG |
| Fluoride | 0.7 mg/L | 4 mg/L | 0.7 mg/L | 1× EWG |
Context
Chromium-6 (hexavalent chromium) — the 'Erin Brockovich chemical' — is detected at 14 times the EWG health guideline. There is no federal MCL specifically for chromium-6; only total chromium is regulated at 100 ppb. California had set a state MCL of 10 ppb but it was withdrawn due to legal challenges and is being re-evaluated.
LA imports approximately 88% of its water from distant sources, making it vulnerable to drought, Colorado River allocation disputes, and quality variations in source water. The blending of multiple sources creates a complex contaminant profile.
Disinfection byproducts (THMs and HAAs) are elevated due to the long distribution system and warm climate, which accelerates byproduct formation. Both exceed EWG guidelines by 50-300x.
PFAS contamination near the 3.2 ppt level is approaching the new EPA MCL of 4 ppt. Several groundwater wells in the San Fernando Valley have been shut down due to elevated PFAS from industrial contamination.
Common questions
Is LA tap water safe to drink?
LA tap water meets all current EPA legal standards. However, 7 of 8 detected contaminants exceed the stricter EWG health guidelines, most notably chromium-6 at 14x the EWG limit and disinfection byproducts at 50-300x. While legally compliant, a reverse osmosis filter significantly improves the quality of LA drinking water.
Does LA water have chromium-6?
Yes. Chromium-6 (hexavalent chromium) is detected in LA water at 0.28 ppb, which is 14 times above the EWG health guideline of 0.02 ppb. There is currently no federal MCL for chromium-6 specifically. Reverse osmosis is the most effective removal method, reducing chromium-6 by 95-99%.
Where does LA get its water?
About 88% of LA's water is imported from three main sources: the Owens Valley via the LA Aqueduct, Northern California via the State Water Project, and the Colorado River via the Colorado River Aqueduct. The remaining 12% comes from local groundwater wells, some of which have been impacted by PFAS contamination.
Does LA water have PFAS?
PFAS has been detected at approximately 3.2 ppt, just below the new EPA MCL of 4 ppt. Several groundwater wells in the San Fernando Valley have been shut down due to PFAS contamination from industrial sources. Reverse osmosis and quality activated carbon filters are effective at removing PFAS.
LA's water quality challenges stem from its reliance on distant imported water and the resulting long distribution system. Chromium-6 is the headline concern — it's the contaminant that made Erin Brockovich famous, and LA's levels exceed the EWG guideline by 14x with no federal limit in place.
a blend of imported water from the Owens Valley Aqueduct, State Water Project (Northern California), Colorado River Aqueduct, and local groundwater wells — approximately 88% imported and 12% local
This data reflects system-wide testing. Your home's plumbing may add or reduce contaminants.
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