Nitrates in well water: the infant risk and how to remove them
Short answer
EPA's limit is 10 mg/L of nitrate as nitrogen. Above that, infants under six months can become seriously ill, so formula must not be made with that water. Don't boil it: boiling concentrates nitrate. A reverse osmosis system at the kitchen tap certified for nitrate is the common fix for drinking water; anion exchange treats the whole house.
Infants under six months: if your well tests above 10 mg/L nitrate-nitrogen, use bottled water for formula. Ask your health department and pediatrician for guidance.
Where nitrate comes from
Fertilizer, manure, livestock areas and septic systems. Shallow wells, sandy soils and wells near fields or septic fields are most at risk. Levels can jump after heavy rain or spring fertilizing, so one clean test isn't the end of the story.
Treatment options
| Option | Covers | Notes |
|---|---|---|
| Reverse osmosis at the kitchen tap | Drinking and cooking | Look for NSF/ANSI 58 certification for nitrate |
| Anion exchange (nitrate-selective resin) | Whole house | Like a softener, but for nitrate; sized from your test |
| Distillation | Small batches | Slow, but effective |
EPA recommends testing nitrate every year. Test again in spring if you live near farmland.
Questions well owners ask
Is it safe for adults to drink water with nitrates?
EPA's 10 mg/L limit is set to protect infants, the most sensitive group. Adults should still avoid long-term drinking above it, and pregnant women should talk to their doctor.
Can a water softener remove nitrates?
A standard softener doesn't. A nitrate-selective anion exchange system works in a similar way but uses different resin.