Nitrite in Drinking Water

EPA Limit: 1 mg/L

The EPA maximum contaminant level for nitrite is 1 mg/L measured as nitrogen. Combined nitrate and nitrite cannot exceed 10 mg/L.

Where Does Nitrite Come From?

Nitrite is typically a short-lived intermediate in the nitrogen cycle and is found less commonly than nitrate. Sources include the same agricultural and septic sources as nitrate. It can also form in water distribution systems from nitrification.

Health Risks

Like nitrate, nitrite can cause methemoglobinemia in infants. It is actually more toxic than nitrate because it directly converts hemoglobin to methemoglobin, reducing the blood's ability to carry oxygen.

What Should I Do?

The same precautions as nitrate apply: do not boil, use bottled water for infants, and consider reverse osmosis or ion exchange filters.