USCanada
ENFR

privatewelldata / Guides / Nitrate

What to do if nitrate is high

Nitrate above 10 mg/L (as nitrogen) is a particular danger for babies.

Why it matters
Comes from fertilizer, manure and septic systems. Can cause methaemoglobinaemia (“blue baby syndrome”) in infants; short exposures above the guideline can cause illness. [Health Canada],[CDC]
US limit
10 mg/L as nitrogen. [US EPA]
Canada limit
10 mg/L as nitrate-nitrogen (45 mg/L as nitrate). [Health Canada]

1. Right away

  • Do not drink the water; use bottled water or another safe source. Boiling does not remove chemicals. [CDC]
  • Infants are most at risk (blue baby syndrome; thyroid effects in bottle-fed infants). Do not use the water to make formula. [Health Canada]

2. Retest and look for the source

  • Common sources are fertilizer, manure, septic systems and sewage. Check for a septic system too close to the well and for manure or fertilizer stored nearby. [Health Canada],[CDC]

3. Treatment

  • Certified options that treat nitrate: reverse osmosis (NSF/ANSI 58) and distillation (NSF/ANSI 62). [Health Canada]
  • Choose a treatment system certified to the NSF/ANSI standard for your specific contaminant, then have an accredited lab test the water going into and coming out of it to confirm it works. [Health Canada]
  • If you cannot find or fix the cause, the options are treatment, a new well, or another safe water supply. [Health Canada]

Who to call

  • Who to call: in the US, contact your county or state health or environment agency (EPA lists them by state). In Canada, contact your local public health office or the provincial drinking-water authority. [US EPA],[CDC],[Health Canada]

Next

Certified labs · What should I test for? · Test costs · Salesperson checklist

Sources

General information, not medical advice.