Nitrate & nitrite · in your tap water
Agricultural runoff · risk to infants
Nitrate and nitrite enter drinking water primarily from agricultural runoff, septic systems, and natural geology. EPA limits nitrate at 10 ppm (measured as nitrogen) and nitrite at 1 ppm — the nitrate limit is high enough to be acutely dangerous to infants under 6 months ('blue baby syndrome' / methemoglobinemia).
If you're using formula or you're pregnant, this one matters acutely — not just long-term. RO at the tap fixes it.
Not sure which system you need? Our reverse-osmosis and whole-home pages compare the options, or book a free Home Water Checkup and we'll test your actual tap.
Every source below was checked to make sure the link works and backs the claim it's next to. These are the primary regulators and peer-reviewed studies — not our opinion.
Nitrate MCL 10 mg/L and nitrite MCL 1 mg/L (as nitrogen); blue-baby-syndrome health effect.
Group 2A: 'probably carcinogenic' under conditions that cause endogenous nitrosation.
Strongest evidence beyond infants: colorectal cancer, thyroid disease, neural-tube defects.
2.7M-person Danish study: elevated colorectal-cancer risk even below the legal limit.
Sources (runoff, septic, geology) and infant methemoglobinemia.
Removal by reverse osmosis (NSF/ANSI 58), ion exchange, and distillation — not carbon.
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Get my free water report Book a free checkupThis page is general water-quality education, not medical advice. Health classifications and limits are attributed to the EPA, EWG, IARC, ATSDR/CDC, WHO and the cited studies. Contaminant levels vary by water system and home — the only way to know what's in your water is to test it. Prepared by SwiftPro Heating, Cooling & Plumbing.