Is tap water safe during pregnancy?

Tap water that meets EPA standards poses no known elevated risk for most pregnant people. The main exception is lead. If your home was built before 1986, your kitchen tap should be tested specifically. City water quality reports reflect system averages, not your individual tap. For PFAS, check whether your area has a known PFAS contamination issue, the EPA's PFAS data site lists affected utilities.

Does tap water affect pregnancy?

At EPA-compliant levels, no documented harm has been established for most tap water contaminants. However, lead crosses the placenta and has been associated with adverse birth outcomes in research, even at low maternal blood levels. PFAS studies have found associations with reduced birth weight and altered thyroid function. These are associations from population research, not confirmed individual-level effects. Your OB can help you evaluate your specific situation.

What water contaminants are risky during pregnancy?

Three contaminants have the strongest documented pregnancy-related research: lead (associated with reduced birth weight and developmental effects at any detectable exposure level), PFAS (associated with reduced birth weight, preeclampsia, and thyroid changes in some studies), and nitrates (associated with adverse outcomes in high-exposure situations, primarily a well water concern in agricultural areas). Most other tap water contaminants at EPA-compliant levels have no established pregnancy-specific risk.

Should I use filtered water when pregnant?

That depends on your water source. If you're in a pre-1986 home, getting a lead test and using an NSF 53-certified filter is a reasonable precaution. If your area has documented PFAS contamination, an under-sink RO system removes 90-99% of PFOA and PFOS. If you're on city water in a post-1986 home with no lead service line and no local PFAS issue, filtering may not be necessary. Ask your OB what they recommend given your local conditions.

Does lead in tap water affect pregnancy?

Research has found associations between maternal blood lead levels and outcomes including reduced birth weight, preterm birth, and developmental effects in children. Lead crosses the placenta. The CDC considers there to be no established safe level of lead exposure for pregnant people or developing children. If you have reason to believe your tap water has elevated lead, test it and address the source before assuming it's fine.

Drinking Water During Pregnancy: Contaminants Worth Knowing About

Most tap water that meets EPA standards poses no known elevated risk during pregnancy. That’’s the accurate baseline, and it’’s worth starting there.

But three contaminants have documented research on pregnancy-related risks that goes beyond general population guidance. Your OB may not mention them at a standard prenatal visit, because most providers assume city water is fine. For most homes, it is. These are the cases where it might not be.

Lead

Lead is the contaminant with the strongest established pregnancy concern of the three.

Lead crosses the placenta. Research has found associations between maternal blood lead levels and reduced birth weight, preterm birth, and developmental effects in children. The CDC’s current reference value for blood lead in children is 3.5 micrograms per deciliter, lowered from 5 micrograms in 2021, reflecting evidence that effects occur at low levels.

The source of lead in tap water isn’t your water system, it’s your home’s plumbing. Homes built before 1986 may have lead solder at pipe joints. Older cities may have lead service lines connecting your building to the water main. Your utility’s water quality report reflects the treatment plant’s output, not what happens as water travels through your pipes.

Getting your kitchen tap tested is a $15-30 certified lab test. Your city health department can refer you to one.

If lead is present, two things address it. An NSF/ANSI 53-certified filter at the kitchen tap reduces lead. An NSF/ANSI 58 reverse osmosis system removes a broader range of contaminants including lead. Draw cold water only. Hot water dissolves more lead from pipes and solder.

PFAS

Research on PFAS and pregnancy is ongoing, and the picture keeps changing as more studies publish.

Studies have found associations between higher PFAS exposure and outcomes including reduced birth weight, preeclampsia, and altered thyroid function. To be precise about what the research shows: these are associations from population-level studies, not confirmed causal effects established in clinical trials. But the associations are consistent enough that the CDC and EPA both list PFAS as a priority research and regulatory concern.

The EPA set new maximum contaminant levels for PFAS in April 2024: 4 parts per trillion for PFOA and PFOS individually. Many utilities are still working toward compliance.

If you’re in an area with a known PFAS contamination issue (the EPA’s PFAS data site lists affected utilities), an under-sink RO system removes 90-99% of PFOA and PFOS. A countertop RO system does the same without permanent installation. Clearly Filtered pitcher has been independently tested for PFAS reduction above 99.5%.

If your utility isn’t on any known PFAS list and your area isn’t near a military base, airport, or industrial facility that uses PFAS-containing foam, your tap likely has minimal PFAS. But checking is straightforward.

Nitrates

Nitrates are primarily a well water risk in agricultural regions.

High nitrate exposure during pregnancy has been associated with adverse outcomes in some epidemiological research, though the evidence base is less extensive than for lead. The EPA’s maximum contaminant level for nitrates is 10 mg/L, and it was originally set with infant health in mind.

City water utilities are required to stay below 10 mg/L and to notify customers when they exceed it. Well water has no such oversight. If you’re on a private well in Iowa, Illinois, Indiana, Nebraska, Kansas, or any agricultural area, test your well for nitrates. A certified lab test costs $15-30.

Boiling doesn’t reduce nitrates. It concentrates them by reducing water volume. The treatment is reverse osmosis (NSF/ANSI 58) or, for well water, source-level intervention.

What’s Not a Documented Pregnancy Risk at Normal Levels

Chlorine in city water at typical tap concentrations (under 4 mg/L) has no established pregnancy-specific harm at those levels.

Fluoride at the HHS-recommended fluoridation level of 0.7 mg/L has no established pregnancy-specific risk at that concentration. Note that this is a different question from what happens at much higher natural fluoride levels.

Typical tap water mineral content, including calcium, magnesium, and sodium at standard tap levels, is not a pregnancy concern for otherwise healthy people.

Staying Hydrated

Water quality matters, but so does volume. Pregnancy increases fluid needs. A common guideline is 8-10 cups of water per day, though your care team may recommend adjusting this based on your individual situation.

Flavor concerns from chlorine are real for some people. If the taste of tap water makes adequate hydration harder, a carbon filter for taste improvement is a practical fix that adds nothing harmful.

The Practical Steps

If you’re in a pre-1986 home, get a certified lead test on your kitchen tap before your third trimester. A $15 test is a clear answer.

If PFAS is a documented concern in your local water supply, an under-sink RO system handles it with the least daily friction.

If you’re on a well in an agricultural area, test for nitrates.

Ask your OB about your specific situation, especially if you know your home is older, if you’re in a region with documented contamination, or if your well hasn’t been tested recently. Your care team can review your local Consumer Confidence Report with you in the context of your specific health history.