Important: If your well water has never been tested for nitrates, use bottled or filtered water for infant formula until you test. Nitrates above 10 mg/L can cause a serious condition in infants under 6 months. If your baby shows breathing difficulty, unusual fatigue, or blue-tinted skin after feeding, call 911 immediately. See your pediatrician with any concerns about your water source.
For most parents on city water, tap water is fine for formula. City water that meets EPA standards is tested regularly and the results are published in your Consumer Confidence Report, which you can request from your utility or find online.
The main risk isn’t your water system’s average quality. It’s what might happen between the treatment plant and your kitchen tap.
The Three Risks Worth Knowing About
Lead
Lead is the primary concern for formula preparation, and it’s a house-specific risk, not a system-wide one.
If your home was built before 1986, you may have lead solder in your pipes. If your building’s water service connects through a lead service line (common in older cities), that’s another exposure point. Lead can leach into water as it sits in pipes, especially overnight.
There is no established safe level of lead exposure for infants. The CDC lowered its blood lead reference value to 3.5 micrograms per deciliter in 2021, down from the previous 5 micrograms. Research links even modest elevations to developmental effects.
Getting your specific tap tested is the only way to know. A certified lab test costs $15-30. Your city health department or water utility can refer you to one.
If you find lead in your tap water, two options cover it. An NSF/ANSI 53-certified filter at the kitchen tap, or an NSF/ANSI 58 reverse osmosis system. Always draw cold water, not hot. Hot water dissolves more lead from pipes and solder.
Flushing your cold tap for 30 seconds before drawing formula water also helps. Letting the water run clears the water that was sitting in the pipes.
Nitrates
Nitrates are primarily a well water risk, not a city water concern in most areas. They’re common in agricultural regions where fertilizer runoff reaches groundwater.
City water utilities are required to keep nitrates below the EPA maximum contaminant level of 10 mg/L. If your city water exceeds that, your utility is required to notify you.
Well water is different. Your well isn’t regulated. Nobody tests it but you.
For infants under 6 months, nitrates above 10 mg/L can interfere with the blood’s ability to carry oxygen. Don’t boil well water to reduce nitrates. Boiling concentrates them by reducing water volume. The only solutions are a reverse osmosis system (NSF/ANSI 58) or using bottled water until you treat the source.
Test your well for nitrates. It’s a $15-30 test at a certified lab. Iowa, Illinois, Indiana, Nebraska, and Kansas have the highest rates of agricultural nitrate contamination, but the risk exists anywhere near farming land.
Bacteria
Bacterial contamination is a well water issue, not a typical city water concern. City water is disinfected.
If you’re on a well that hasn’t been tested recently, or if your area experienced flooding in the past year, test for coliform bacteria before using it for formula. A basic bacteria and coliform test costs $30-50 at a county-certified lab.
If you need to use potentially contaminated well water in an emergency, boiling (full rolling boil for 1 minute) kills bacteria and viruses. But again, boiling doesn’t remove lead or nitrates.
Distilled Water: Fine, But Not Required
Distilled water is fine for formula. It contains essentially no dissolved solids, including no lead and no nitrates.
The American Academy of Pediatrics doesn’t require distilled water unless there’s a specific contamination concern. If your tap water tests clean and you’re in a post-1986 home with no lead service line, plain tap water is appropriate.
If you have any uncertainty about your water source and want a simple precaution, distilled water is a reasonable choice. Most grocery stores carry gallon jugs for $1-2.
One note: if you’re using RO-filtered water (which has very low fluoride), talk to your pediatrician about fluoride supplementation. The AAP supports fluoride supplementation in formula when local water has low fluoride content. An RO system removes most fluoride, which is something to discuss with your care team.
Hot Tap Water: Never Use It
Always draw cold water for formula, then heat it.
Hot water from your tap dissolves more lead from pipes and solder than cold water. Hot water heaters also accumulate sediment over time. Cold water from the tap, filtered or tested, is the correct starting point.
NSF-Certified Filter: The Direct Solution
If you want to address lead and PFAS at the same time without testing everything individually, an NSF-certified filter at your kitchen tap handles both.
Clearly Filtered pitcher: NSF/ANSI 42, 53, and 401 certifications, independently tested for PFAS above 99.5% reduction and lead above 99.5% reduction. Around $65 for the pitcher. Zero installation.
Under-sink RO system: broader contaminant coverage, higher flow rate, NSF/ANSI 58 certified. More cost, more installation, more coverage.
Either way, use cold filtered water. Never hot tap.
The Practical Bottom Line
If you’re on city water in a post-1986 home with no lead service line, run cold water from your kitchen tap for 30 seconds before drawing formula water. That clears sitting water from your pipes and is a practical, no-cost precaution.
If you have any doubt about lead or PFAS in your water, a Clearly Filtered pitcher is $65 and gives you NSF-documented protection with no installation required.
If you’re on a well, test for nitrates before using the water for formula. Don’t skip this.
Ask your pediatrician about your specific situation, especially if you’re in an area with known contamination.
Related: Lead in Tap Water | Nitrates in Well Water | Best Pitcher Water Filters