Is chromium-6 in my drinking water?

Most likely yes. The EWG found chromium-6 in tap water serving 218 million Americans across all 50 states. It occurs naturally in many rock formations and also enters water from industrial contamination. Since there's no federal MCL specifically for chromium-6, most utilities aren't required to test for or treat it. Check the EWG Tap Water Database for your city's levels.

What filter removes chromium-6?

Reverse osmosis is the most effective residential option, removing 95-99% of chromium-6. Ion exchange systems are also effective. Standard carbon filters have limited effectiveness — don't rely on a basic Brita-type pitcher for chromium-6 removal. The Aquasana OptimH2O is one of the few specifically certified for chromium-6 reduction.

Why is there no federal limit for chromium-6?

The EPA regulates total chromium (which includes both chromium-3 and chromium-6) at 100 ppb, but has not set a separate standard for the more toxic chromium-6 form. California attempted to set a state MCL of 10 ppb but it was struck down in court on procedural grounds and is being re-established. The regulatory gap means chromium-6 levels that the EWG considers dangerous are technically legal.

heavy metal

Chromium-6 (Hexavalent Chromium) in Drinking Water

Updated: 2026-05-16Written by: TapWaterGuide Editorial Team

What is Chromium-6 (Hexavalent Chromium) and is it dangerous in tap water? Chromium-6 (Hexavalent Chromium) is a heavy metal contaminant found in drinking water. There is currently no federal EPA limit for Chromium-6 (Hexavalent Chromium). The stricter EWG health guideline is 0.02 ppb. Health effects include cancer when ingested in drinking water — stomach and intestinal cancers and liver damage and disrupted liver function. The most effective removal methods are Reverse Osmosis, Ion Exchange, Distillation.

Last updated: 2026-05-16 · Source: EPA, WHO, EWG

Regulatory Limits

EPA MCL

None

No federal MCL for chromium-6 specifically. Only total chromium is regulated at 100 ppb. California set a state MCL of 10 ppb but it was legally challenged.

EWG Guideline

0.02 ppb

Based on California's public health goal for cancer risk from ingestion.

MCLG (Goal)

0 ppb

The level at which no known health effects occur

Health Effects

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Cancer when ingested in drinking water — stomach and intestinal cancers

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Liver damage and disrupted liver function

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Kidney damage with chronic exposure

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Reproductive and developmental harm

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Allergic dermatitis from skin contact (occupational exposure)

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Made famous by the Erin Brockovich case involving PG&E contamination in Hinkley, California

Especially vulnerable: Children, People with liver or kidney conditions, Pregnant women

How to Remove Chromium-6 (Hexavalent Chromium) from Water

Technology	Effectiveness	Notes
Reverse Osmosis	high	Removes 95-99% of chromium-6. Most effective residential method.
Ion Exchange	high	Strong base anion exchange resins are effective for chromium-6 removal.
Activated Carbon	low	Standard carbon filters have limited effectiveness for chromium-6. Some specialty carbon blocks claim moderate removal.
Distillation	high	Effective but slow and energy-intensive for daily use.
Water Softener	none	Water softeners do NOT remove chromium-6.

Where Chromium-6 (Hexavalent Chromium) Is Most Common

California — detected in water systems serving 90%+ of the state's population

Phoenix, AZ and the greater Southwest — naturally occurring in desert groundwater

Chicago, IL — industrial legacy contamination

Oklahoma City, OK — naturally occurring

The EWG found chromium-6 in tap water of 89% of cities sampled nationwide

Common sources include: Natural erosion of chromium deposits in rock formations, Industrial discharge from chrome plating, steel manufacturing, and leather tanning, Coal-burning power plant ash and waste disposal, Contaminated groundwater from industrial sites (like the Hinkley, CA case).

Best Filters for Chromium-6 (Hexavalent Chromium) Removal

We've tested and compared the top water filters that are NSF-certified to remove Chromium-6 (Hexavalent Chromium). Each recommendation is matched to specific contaminant removal performance, not just marketing claims.

View our top chromium-6 (hexavalent chromium) filter picks →