Drinking Water Nitrate PPM Checker
Nitrate in well water is the quiet risk for infants and pregnant women — the WHO limit is 50 PPM. Fertilizer runoff and septic systems are the usual culprits. Enter your test result for a clear safe/unsafe verdict.
Calculator
Drinking Water Nitrate PPM Checker
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Nitrate in well water is the quiet risk for infants and pregnant women — the WHO limit is 50 PPM. Fertilizer runoff and septic systems are the usual culprits. Enter your test result for a clear safe/unsafe verdict.
How to use this calculator
- Enter nitrate PPM from your test.
- See the WHO-limit verdict.
- Get next steps if over.
The formula
Bands keyed to the 50 PPM WHO guideline (as nitrate).
What the units mean
PPM (parts per million) — one part of solute per million parts of the total mixture. The workhorse unit for trace concentrations in water, air, and food.
Worked example
Well test: 65 PPM → over the limit — do not use for infant formula; consider treatment.
Quick reference
| Reading | Status |
|---|---|
| <25 PPM | Good |
| 25–50 PPM | Watch |
| >50 PPM | Over WHO limit |
As nitrate (NO₃).
Where you will actually use this
You cannot taste, smell, or see nitrate. Testing is the only way to know.
- Well water safety
- Rural water testing
- Agricultural areas
Mistakes that give wrong answers
- Confusing nitrate with nitrite (different limits)
- Testing once and assuming it never changes
Key takeaways
- Formula: WHO limit: 50 PPM as nitrate (11 PPM as nitrate-nitrogen)
- Remember: As nitrate (NO₃).
- Watch out for: Confusing nitrate with nitrite (different limits)
- Next step: run your own numbers in the calculator above, then verify with a measurement — calculated values are only as good as the inputs.
Frequently asked questions
What is the safe nitrate level in drinking water?
Below 50 PPM (WHO).
Why is nitrate dangerous for babies?
It can cause "blue baby syndrome" (methemoglobinemia).