Water Quality During Pregnancy: A Complete Guide

Priority contaminants during pregnancy

Pregnancy changes how your body processes water and what contaminants can do to a developing fetus. Several common drinking water contaminants cross the placental barrier or disrupt hormones at levels that would be harmless to non-pregnant adults. Knowing which ones matter most helps you focus your testing and filtration budget where it counts.

Lead

Lead crosses the placental barrier freely. The CDC and EPA agree there is no safe level of lead exposure, and this is especially true during pregnancy. Exposure is associated with low birth weight, preterm birth, developmental delays, and reduced IQ in the child. The EPA\'s action level for lead in drinking water is 15 parts per billion (ppb), but health researchers have documented effects well below that threshold. Homes built before 1986 are at highest risk because lead solder was used in plumbing until that year. Even newer homes can have fixtures that leach small amounts of lead. Learn more about lead in drinking water.

PFAS (forever chemicals)

PFAS are associated with preeclampsia, thyroid disruption, reduced immune response in newborns, and lower birth weight. The EPA set enforceable limits in 2024: 4 parts per trillion (ppt) for PFOS and PFOA individually. Many water systems still exceed these levels and have until 2029 to comply. If you are pregnant or planning pregnancy, you should not wait for utility compliance. Read our detailed PFAS and pregnancy guide.

Nitrate

The EPA maximum contaminant level (MCL) for nitrate is 10 mg/L. Above this level, nitrate interferes with the blood\'s ability to carry oxygen, a condition called methemoglobinemia. This risk is highest for developing fetuses and infants under six months. Nitrate contamination is most common in agricultural areas where fertilizer runoff enters groundwater. If you live in a farming region, testing for nitrate is especially important.

Disinfection byproducts (DBPs)

When chlorine reacts with organic matter in water, it creates trihalomethanes (THMs) and haloacetic acids (HAAs). The EPA limits total THMs to 80 ppb and HAAs to 60 ppb. Some epidemiological studies have linked high THM exposure during the first trimester to increased miscarriage risk, though the evidence is not conclusive. Surface water systems that use chlorine tend to have higher DBP levels than groundwater systems.

Arsenic

The EPA MCL for arsenic is 10 ppb. Arsenic exposure during pregnancy is associated with reduced fetal growth, preterm birth, and stillbirth in some studies. Groundwater sources in the western and southwestern United States have the highest natural arsenic levels.

Recommended testing schedule

If you are pregnant or planning pregnancy, test your tap water for these contaminants at minimum. Testing costs $100 to $300 depending on what you include.

Contaminant	When to test	Why	Cost
Lead	Before pregnancy or first trimester	No safe level; comes from your home plumbing	$20-40
PFAS	Before pregnancy or first trimester	Accumulates in body; hard to eliminate once exposed	$100-200
Nitrate	Before pregnancy; retest if on well water	Levels fluctuate seasonally in agricultural areas	$15-25
Disinfection byproducts	Summer months (levels peak in warm weather)	Highest risk in first trimester	$50-100
Arsenic	Once, if on well water or in western US	Naturally occurring; does not change seasonally	$20-30

Homes built before 1986 should prioritize lead testing due to lead solder risk. Homes near military bases, airports, or industrial sites should prioritize PFAS testing. Check your city\'s water data for known contamination before deciding what to test.

How to reduce exposure: step by step

1. Check your city\'s water report. Search your city on CheckMyTap to see lead, PFAS, hardness, and other contaminant data. This tells you what to focus on.
2. Test your specific tap. City averages do not reflect your home\'s plumbing. Order a certified lab test from a state-accredited laboratory. Your state health department website lists certified labs.
3. Install point-of-use filtration. An NSF 53 certified carbon block filter or reverse osmosis system at the kitchen tap removes lead, PFAS, and most contaminants of concern. Budget $100 to $300 for a quality under-sink system. See our under-sink filter guide.
4. Use filtered cold water only. Hot tap water dissolves more lead and metals from pipes. Always start with cold filtered water for drinking, cooking, and making beverages.
5. Flush pipes after stagnation. If water has been sitting in pipes for more than 6 hours (overnight, after work), run the cold tap for 30 seconds to 2 minutes before using it for drinking or cooking. This flushes out water that has been in contact with plumbing the longest.

Filtration options compared

Filter type	Removes lead	Removes PFAS	Removes nitrate	Cost
Carbon block (NSF 53)	Yes	Most types	No	$50-150
Reverse osmosis	Yes	Yes	Yes	$150-400
Pitcher (Clearly Filtered)	Yes	Yes (NSF P473)	No	$50-80
Standard Brita pitcher	No	No	No	$20-35

For pregnancy, a reverse osmosis system provides the broadest protection because it removes lead, PFAS, nitrate, arsenic, and disinfection byproducts in a single system. If budget is a concern, a Clearly Filtered pitcher certified for PFAS and lead is a solid interim solution.

What about well water?

If your home uses a private well, you are responsible for your own testing. The EPA does not regulate private wells. The CDC recommends testing well water annually for bacteria, nitrate, and pH, and more frequently during pregnancy. Wells near agricultural land should be tested for pesticides and nitrate. Wells in areas with naturally occurring arsenic or radium need those specific tests. Contact your county health department for local testing recommendations.

Related resources

• PFAS and pregnancy: detailed guide
• Lead in drinking water
• Safe water for baby formula
• Under-sink filter buying guide
• Check your city\'s water quality