Nitrate in Drinking Water
EPA limits, health effects, and what to do if your water is affected.
🩨 Health Effects
Nitrate is acutely dangerous for infants under 6 months, causing methemoglobinemia ("blue baby syndrome") where the blood loses its ability to carry oxygen. For adults and older children, short-term exposure above the MCL may cause similar issues. Long-term exposure at lower levels is being studied for possible cancer links.
📍 Sources in Water
The primary source is agricultural fertilizer runoff, which enters groundwater and streams. Animal waste from feedlots and septic system leakage also contribute significantly. Nitrate is most common in rural agricultural areas and in surface-influenced groundwater.
✅ What To Do
Do not give tap water above the MCL to infants or use it to mix formula. Boiling does NOT remove nitrate; it concentrates it. Use bottled water or a reverse osmosis filter (NSF/ANSI 58 certified) for infant formula and drinking water. Pregnant women should also use caution.
Check your tap water for Nitrate
Search your ZIP code to see if your water system has had Nitrate violations, plus lead testing results and an overall safety grade.
Search your ZIP code →Data from the EPA's Safe Drinking Water Information System (SDWIS). MCLs reflect minimum federal standards; some contaminants may pose health risks below these thresholds.