Contaminant · Health
What Nitrate is, where it hides, and what actually removes it.
A farm-country concern, especially for infants.
Short answer
Nitrate reaches groundwater from fertilizer, manure and septic systems. It matters most in wells feeding formula for infants under six months.
Where it comes from
Rural areas with intensive agriculture; shallow wells near feedlots and fertilized fields.
- •Fertilizers and manure
- •Septic systems
- •Atmospheric deposition
Last reviewed September 2026
Health context
What Nitrate does to health
Grouped by who is most affected, with the practical steps that follow from it. This is a plain-language summary, not our own testing.
Infants
High nitrate can cause "blue baby syndrome" (methemoglobinemia) in the first months of life.
What to do about it
- •Test annually for nitrate if you are on a well.
- •For infants, use bottled or RO-treated water until the well retests below the MCL.
- •Whole-home options are costly — point of use is the standard fix.
Regulatory source
Read the EPA page for Nitrate →
Certified (NSF/ANSI or WQA listing for the exact model) is not the same as a manufacturer "claims-only" statement on a product page.
Test before you treat
How to actually test for it
DIY strips mislead for many contaminants. Here’s the honest method for finding Nitrate.
Lab test for nitrate-nitrogen
EPA MCL is 10 mg/L as nitrogen; the sample must be taken at the well.
Filter guidance
What actually removes it (and what does not)
Certification matters more than a marketing claim. Here’s the ranking.
RO
Reverse osmosis at the tap is a low-cost certified fix.
Ion exchange
Nitrate-selective resin works but needs regeneration and maintenance.
Normalized database
Compare certified options
Same contaminants, same columns, real source links. Blanks mean “not stated” — we don’t invent numbers.
| Product | NSF |
|---|---|
iSpring WGB32B 3-Stage Whole House Activated carbon | NSF 42 — not statedNSF 53 — not statedNSF 58 — not statedNSF 401 — not stated |
Express Water Heavy Metal Whole House 3-Stage Activated carbon | NSF 42 — not statedNSF 53 — not statedNSF 58 — not statedNSF 401 — not stated |
APEC ROES-50 Essence 5-Stage RO RO | NSF 42 — not statedNSF 53 — not statedNSF 58 certifiedNSF 401 — not stated |
AquaTru Glass Carafe Countertop RO RO | NSF 42 certifiedNSF 53 certifiedNSF 58 certifiedNSF 401 certified |
ProOne Big+ Gravity Countertop Filter Composite | NSF 42 — not statedNSF 53 — not statedNSF 58 — not statedNSF 401 — not stated |
FAQ
Common questions
+Is Nitrate in my tap water?
Only a certified lab test (not a taste test or a strip) answers that reliably.
+Does boiling remove Nitrate?
No. Boiling concentrates most contaminants rather than removing them.
+What's the safest first step?
Test before you treat, then choose a filter type certified for Nitrate.