Are nitrates in drinking water safe during pregnancy?

What's actually in it

Nitrates get into drinking water mostly from agricultural fertilizer runoff and septic systems. The EPA limit for nitrates in public drinking water is 10 mg/L, but research suggests that limit may not be protective for pregnant women and infants.

When you drink water with nitrates, your body converts them to nitrites. Nitrites bind to hemoglobin and reduce its ability to carry oxygen. For a developing fetus that depends entirely on the mother's blood for oxygen, this is a real concern.

What the research says

A 2026 scoping review in a mammalian prenatal study found that nitrate and nitrite intake during pregnancy is linked to effects on fetal development, including increased risk of certain birth defects and impaired growth. The review found effects occurring at exposure levels common in areas with agricultural water contamination.

Infants are the most vulnerable because their digestive systems convert nitrates to nitrites more efficiently than adults. This is why infant formula should never be mixed with well water or water from areas with known nitrate issues.

Check your local water quality report for nitrate levels. If you're pregnant and your tap water is above 5 mg/L, a reverse osmosis filter is the most effective way to remove nitrates.