Why Infants Need Special Water Precautions
Infants consume more water per unit body weight than any other age group — primarily through formula, which is mixed with water, and directly through breast milk from exposed mothers. Because PFAS bioaccumulate and infants’ developing organ systems are more sensitive to toxicant exposure, even the small amounts of PFAS in typical tap water can have proportionally greater effects in infants than in adults.
The EPA’s 4 ppt MCLs for PFOA and PFOS were set with consideration of sensitive populations including infants fed formula reconstituted with tap water. For infants in households with water exceeding these standards — or for parents who want to minimize any PFAS exposure — certified filtration provides meaningful protection.
Choosing Water for Formula Preparation
Reverse osmosis filtered water is the gold standard for formula preparation in households with PFAS concerns. RO systems certified by NSF International to Standard 58 for PFAS removal provide water with 90–99% PFAS reduction. Under-sink RO units are practical and relatively affordable for this purpose.
Bottled water marketed for infant formula — typically purified or spring water — should be checked against the brand’s quality reports for PFAS testing. Some bottled water brands do not test for PFAS, and several have been found to contain detectable PFAS. NSF-certified RO filtered tap water is often a more reliably PFAS-free option than unverified bottled water.
Solid Foods and Water Exposure in Older Infants
As infants transition to solid foods, water used in cooking — for rice, oatmeal, pureed vegetables — becomes an additional PFAS exposure route. Using filtered water for cooking infant foods applies the same protection as for formula. Store-bought jarred and pouched infant foods are generally not prepared with tap water and are unlikely to be significant PFAS sources.
Introducing sippy cups with tap water at around 6 months of age, as commonly recommended, represents a transition point where filtered water should be provided if tap water PFAS levels are a concern. Pediatricians in communities with known PFAS contamination are increasingly advising patients about water filtration options.