Nitrate in Drinking Water

EPA Limit: 10 mg/L

The EPA maximum contaminant level for nitrate is 10 mg/L measured as nitrogen. Nitrate violations are among the most common health-based violations in agricultural states.

Where Does Nitrate Come From?

Nitrate contamination primarily comes from agricultural fertilizer runoff, animal waste, septic systems, and municipal wastewater discharge. It is one of the most common groundwater contaminants in agricultural areas.

Health Risks

High nitrate levels are most dangerous for infants under six months, causing methemoglobinemia ('blue baby syndrome'), a condition where the blood cannot carry enough oxygen. Adults may experience thyroid effects from long-term exposure.

What Should I Do?

Do not boil water to reduce nitrate — boiling concentrates it. Use bottled water for infant formula if nitrate levels are elevated. Reverse osmosis, ion exchange, and distillation filters can remove nitrate. Standard carbon filters do not.