What to do if arsenic is high

Arsenic is a long-term risk: health effects come from years of exposure.

Why it matters: Occurs naturally in some areas. Long-term exposure increases the risk of lung, bladder, liver and skin cancer. ^{[Health Canada]}
US limit: 0.010 mg/L (10 µg/L). ^{[US EPA]}
Canada limit: 0.010 mg/L, kept as low as reasonably achievable. ^{[Health Canada]}

1. Right away

Use bottled water or another safe source for drinking and cooking. Boiling does not remove arsenic. ^[CDC]
For many chemicals, health problems come from exposure over several years; a high result needs more sampling and corrective action. ^{[Health Canada]}

Common filters (NSF/ANSI 53) and reverse osmosis (NSF/ANSI 58) remove only pentavalent arsenic (arsenic V). Ask the lab which form is in your water before you buy. ^{[Health Canada]}
Distillation (NSF/ANSI 62) is certified for arsenic. Removing iron first also helps, because iron holds on to arsenic. ^{[Health Canada],[Health Canada]}
Choose a treatment system certified to the NSF/ANSI standard for your specific contaminant, then have an accredited lab test the water going into and coming out of it to confirm it works. ^{[Health Canada]}

Who to call: in the US, contact your county or state health or environment agency (EPA lists them by state). In Canada, contact your local public health office or the provincial drinking-water authority. ^{[US EPA],[CDC],[Health Canada]}

General information, not medical advice.