Nitrate in Drinking Water: Risks, Sources, and Solutions
Why nitrate matters, especially for infants, and how to reduce it.
Why nitrate is dangerous for babies
Nitrate (NO3) above 10 mg/L can cause methemoglobinemia (blue baby syndrome) in infants under 6 months. Nitrate converts to nitrite in the digestive system, which reduces the blood's ability to carry oxygen. Adults can tolerate higher levels, but pregnant women should also limit exposure. The EPA Maximum Contaminant Level is 10 mg/L.
Where it comes from
Agricultural runoff (fertilizer and animal waste) is the primary source. Septic systems, wastewater discharge, and natural geological deposits also contribute. Cities near intensive farming operations (Central California, Iowa, Nebraska) tend to have elevated nitrate. Check your city's nitrate level.
Removal
Reverse osmosis removes 85-95% of nitrate. Ion exchange resin specifically designed for nitrate (different from water softener resin) is also effective. Standard carbon filters do NOT remove nitrate. Boiling actually concentrates nitrate, making it worse. If your water exceeds 10 mg/L and you have an infant, use bottled water for formula preparation until filtration is installed.