What is nitrate in water?
Nitrate is a compound formed from nitrogen. In water it comes mostly from human activity at the surface — lawn and agricultural fertilizer, manure, and septic systems — that works its way down into groundwater. It's colorless, tasteless, and odorless.
It's most common in rural and agricultural areas and on private wells, especially shallower ones. City systems monitor and manage nitrate; well owners are on their own to test for it.
Why nitrate in water matters
Nitrate's signature risk is to infants under six months, where high levels can interfere with the blood's ability to carry oxygen — the reason it's taken so seriously. It's also a concern during pregnancy. The federal limit is 10 parts per million.
Two things surprise people. First, the everyday water fixes don't touch it: a water softener and a carbon filter do essentially nothing for nitrate. Second, boiling the water makes it worse — the water evaporates and the nitrate concentrates. So the usual instincts don't help here.
What to do about nitrate in water
Nitrate needs a treatment method built for it:
- Reverse osmosis at the kitchen sink is the most common home solution for drinking and cooking water.
- Anion-exchange systems can treat larger volumes or the whole house where needed.
If you're on a private well — especially in a rural or farm area — nitrate is near the top of the list to test for. Our free in-home visit is a starting point, and we'll walk you through the Minnesota Department of Health testing schedule for wells so nothing important gets skipped.