Chromium and Hexavalent Chromium (Chromium-6) in Well Water
Short answer: EPA's limit for public water is 100 µg/L (0.1 mg/L) of total chromium. Health Canada's maximum is 50 µg/L (0.05 mg/L) total chromium, set to protect against chromium-6. There is no separate federal limit for chromium-6.
Official limits
| Item | US EPA | Health Canada |
|---|---|---|
| Total chromium | 0.1 mg/L (100 µg/L) | 0.05 mg/L (50 µg/L) |
Where it comes from
Health Canada lists natural erosion of minerals and industrial releases or spills as common sources. Chromium-6 (hexavalent) is the form linked to cancer; chromium-3 is a nutrient in small amounts.
How to test
- Total chromium: metals scan, often EPA method 200.8 (ICP-MS).
- Chromium-6: ask for EPA method 218.6 or 218.7. Not every lab offers it.
What results mean
Compare total chromium with the limits above. If you live near a past industrial site or your total chromium is detectable, ask about a chromium-6 test. Reverse osmosis and ion exchange are common treatment types; check the device certification and retest.
Sources
- EPA: National Primary Drinking Water Regulations
- Health Canada: Guidelines for Canadian Drinking Water Quality, summary table (Dec 2025)
- EPA: Chromium in drinking water
Questions
Is there an EPA limit for chromium-6?
No separate federal limit. EPA's 0.1 mg/L limit covers total chromium, which includes chromium-6.
What test do I order for chromium-6?
Ask a certified lab for EPA method 218.6 or 218.7. A regular metals test reports total chromium only.
What is Canada's chromium guideline?
Health Canada's maximum acceptable concentration is 0.05 mg/L for total chromium.
Free well water checklist
15 family-friendly steps based on CDC and EPA guidance. Print it, keep it on the fridge, and know when to call a certified lab.
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