Arsenic in well water: the New York limit and what to do

As of 2026-10-07. From the New York State Department of Health (NYSDOH) and US EPA. Private wells aren't regulated like public water: NYSDOH recommends public-water limits for private wells. Sources are linked below.
Arsenic over the limit? NYSDOH: "Stop using your water and use bottled water for drinking, preparing food, or making ice if water tests show contaminants in your well water or if you suspect your well could be contaminated." Then call your local health department.

The limit

TestNew York (NYSDOH Fact Sheet #3)US EPA (public water)
Arsenic0.01 mg/L0.010 mg/L

These limits apply to public water systems. Private wells aren't required to meet them, but health departments use them as guidance.

NYSDOH says the limits in its fact sheet "are based upon requirements for Public Water Supply systems and are also recommended for use on individual residential systems." The fact sheet notes that mg/l means milligrams per liter (parts per million), so 0.01 mg/L is the same as 10 micrograms per liter (10 parts per billion). Check which unit your report uses; if it doesn't say, ask your lab.

Why it matters

NYSDOH (Test Your Well): long-term exposure "is associated with nerve and liver damage, cancer, high blood pressure and damage to blood vessels of the heart and brain." Its Fact Sheet #3 lists the concern as "Cancer of the skin, bladder, lungs, kidneys and liver." EPA lists "Skin damage or problems with circulatory systems, and may have increased risk of getting cancer" from long-term exposure above its limit.

Where it comes from

EPA lists the sources as "Erosion of natural deposits; runoff from orchards, runoff from glass and electronics production wastes." NYSDOH's Fact Sheet #3 suggests testing for arsenic (along with nitrate, pesticides and coliform bacteria) near "areas of intensive agriculture." NYSDOH's Private Well Risk Mapper lets you "view risks to your private wells from flooding, agricultural runoff, and arsenic contamination" for an address.

How often to test

NYSDOH says to test "at least once a year for bacteria and every 3-5 years for the other contaminants listed," and arsenic is on that list. Use a NYSDOH ELAP-certified lab. See also how often to test well water.

If your result is high

  1. Switch to bottled water for drinking, preparing food and making ice, and call your local health department (NYSDOH).
  2. Ask your health department about retesting and whether arsenic has been found in local groundwater.
  3. Ask about treatment. Where NYSDOH doesn't cover a point, we cite the Minnesota Department of Health: "MDH recommends working with a water treatment professional to make sure your treatment unit/system effectively removes arsenic." Its home water treatment fact sheet compares unit types.

Reading the rest of your report? See well water test results explained.

Common questions

What is the arsenic limit for a private well in New York?

NYSDOH Fact Sheet #3 lists 0.01 mg/L for arsenic. It says its limits are based on public water supply requirements "and are also recommended for use on individual residential systems." These limits apply to public water systems. Private wells aren't required to meet them, but health departments use them as guidance.

How often should I test my well for arsenic?

NYSDOH's Test Your Well page lists arsenic under "Every 3-5 years," and says to test "at least once a year for bacteria."

How do I find out whether arsenic has been found near me?

NYSDOH says: "Contact your Local Health Department to determine if arsenic has been detected in local groundwater." Its Private Well Risk Mapper also shows arsenic risk for an address.

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Sources

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