Nitrate in well water, infants and what to do

Nitrate in well water is a serious concern for infants because high levels can keep blood from carrying oxygen the way it should. If your well water has not been tested recently, or if a lab report shows nitrate above the EPA drinking water standard of 10 milligrams per liter as nitrogen, do not use that water for infant formula, baby food, or a baby’s drinking water until you switch to bottled water or another known-safe source. (epa.gov)

Why infants are at higher risk

Nitrate is a chemical form of nitrogen that can get into groundwater from fertilizers, septic systems, wastewater, animal waste, polluted runoff, and even decaying plants. You usually cannot see, smell, or taste it in water. For private wells, that means testing is the only reliable way to know if there is a problem. (cdc.gov)

Bottle-fed babies under 6 months old are the group most often warned about by health agencies. In a baby’s body, nitrate can be changed into nitrite, and nitrite can interfere with how blood carries oxygen. That can lead to methemoglobinemia, often called blue baby syndrome. Minnesota health officials say babies at this age are at the highest risk, and EPA warns that infants under 6 months can become seriously ill if water is over the standard. (health.state.mn.us)

This is also why pregnancy and newborn planning matter. CDC says to test a well if someone in the home becomes pregnant or if a child starts living with you. Wisconsin DNR also says to test for nitrate once a year and before the well will be used by a woman who is or may become pregnant. Guidance can vary by state, so it is smart to check your local health department or state well program too. (cdc.gov)

What number on your report matters

For drinking water, the EPA maximum contaminant level, or MCL, for nitrate is 10 mg/L when the result is reported as nitrogen. You may see that written as nitrate as nitrogen, nitrate-N, or NO3-N. The EPA MCL for nitrite is 1 mg/L as nitrogen, and the combined nitrate plus nitrite standard is 10 mg/L as nitrogen. (epa.gov)

Lab reports can be confusing because some labs report nitrate as nitrate ion instead of nitrate as nitrogen. Colorado State University Extension notes that 10 mg/L as nitrate-nitrogen is equivalent to 45 mg/L as nitrate. So before you panic, make sure you are reading the right units. If you need help, see How to read a water test report: MCLs, units and flags. (extension.colostate.edu)

For infant feeding, keep the message simple. If your report is over the EPA nitrate standard, or if you are not sure how to read the report, do not use that well water for formula or baby food until you get clear guidance and a safe source of water. (epa.gov)

What to do right now if there is a baby in the home

If you are expecting a baby, feeding an infant, or trying to sort out a recent nitrate result, this checklist can help:

1. Stop using untested or high-nitrate well water for infant formula, baby cereal, or any food or drink made with water for a baby under 6 months. (epa.gov)
2. Switch to bottled water or another water source that is known to meet drinking water standards. EPA says bottled water is the quickest short-term option when nitrate exceeds the MCL. (epa.gov)
3. If a baby’s skin turns blue or gray, especially around the eyes or mouth, or the baby seems suddenly very ill, get emergency medical care right away. Minnesota health officials warn that methemoglobinemia can cause blue skin color and can lead to serious illness or death. (health.state.mn.us)
4. Arrange a test through a state-certified drinking water lab. You can start with the state-by-state directory and this guide on How to choose a state-certified drinking water lab. CDC recommends using a state-certified laboratory for private well testing. (cdc.gov)
5. Ask your local health or environmental department whether you should also test for bacteria or other chemicals. CDC notes that if nitrate is high, other harmful chemicals or germs may also be present. (cdc.gov)

One more practical point: if you are not sure what to ask for, use a planning tool before you order. A simple starting point is the Well water test planner, then follow the lab’s instructions closely when sampling. (cdc.gov)

How to test your well the right way

CDC says all well owners should test well water at least once each year for total coliform bacteria, nitrates, total dissolved solids, and pH. CDC also says to test if there is flooding or nearby land disturbance, if you repair part of the well system, if the water changes in taste, color, or smell, if someone becomes pregnant, or if a child starts living in the home. (cdc.gov)

That yearly nitrate test matters even if last year’s result was fine. Nitrate levels can change with season, rainfall, land use, and local groundwater conditions. Colorado State University Extension says seasonal variation can happen, and if a result is high or borderline high, retesting every 3 to 6 months may be appropriate. (extension.colostate.edu)

Good sampling matters too. A bad sample can create confusion and delay. Use the bottle and instructions from the lab, keep the sample cool if the lab tells you to, and get it back on time. If you want a refresher before you collect, read How to collect a well water sample without ruining the test. (extension.colostate.edu)

If you are not sure what else to test for beyond nitrate, your local health department can help you narrow it down based on where you live and what is near your well. You can also review What to test your private well water for (and how often). Because local advice can differ, especially after flooding or during pregnancy, confirm your next steps with the relevant official office where you live. (cdc.gov)

Can boiling or filters fix nitrate?

Boiling does not remove nitrate. In fact, both Minnesota health officials and Colorado State University Extension say boiling can make nitrate more concentrated as water evaporates. So boiling unsafe well water is not a safe way to make formula. (health.state.mn.us)

For short-term safety, EPA says to use a safe alternative water supply, with bottled water as the quickest option. For treatment, EPA lists reverse osmosis and distillation as options, and Colorado State University Extension also lists ion exchange units for nitrate removal. (epa.gov)

Be careful with assumptions about everyday filters. Colorado State University Extension says charcoal filters and standard water softeners do not adequately remove nitrates. That is why a filter that helps with taste or odor is not automatically a nitrate solution. If you are shopping for treatment, make sure the device is meant for nitrate removal, not just general filtration. (extension.colostate.edu)

Treatment is not always the only long-term answer. Depending on the cause, families may also need to inspect the well, look for nearby contamination sources, repair the system, or consider a different water source. CDC notes that local health or environmental departments can help explain what to do next after a harmful result. (cdc.gov)

Why nitrate can be a warning sign, not just a single number

A high nitrate result sometimes points to a bigger well safety issue. CDC notes that nitrate can enter private wells from septic systems, wastewater, flooded sewers, stormwater runoff, fertilizers, runoff from farms, animal waste, and decaying plants. Some of those same pathways can also let bacteria or other chemicals into a well. (cdc.gov)

That is one reason health agencies do not want families to focus on one contaminant alone. A nitrate problem can be a signal to check the well’s condition, review what is happening uphill or nearby, and ask whether you should add tests for bacteria or local contaminants of concern. (cdc.gov)

Heavy rain and flooding deserve extra attention. EPA advises testing wells after flooding, especially if floodwater covered the well, and CDC says flooding or nearby land disturbance is a reason to test. If your well is in an area with recurring runoff problems, put regular nitrate testing on your calendar before the next wet season. (epa.gov)

Frequently asked questions

Can I boil the water and use it for baby formula?

No. Boiling does not remove nitrate, and it can raise the nitrate concentration as water evaporates. If your water is over the nitrate standard, or if you do not have a recent test result, use bottled water or another known-safe source for infant formula and baby food instead. (health.state.mn.us)

How often should I test my well for nitrate?

CDC says to test at least once every year. Test sooner if someone becomes pregnant, a child starts living in the home, the well is repaired, flooding happens, or the water changes in taste, smell, or color. Some states add more specific advice. For example, Wisconsin DNR says to test nitrate once a year and before the well will be used by a woman who is or may become pregnant. (cdc.gov)

My result is 8 or 9 mg/L. Is that okay for a baby?

If that result is reported as nitrate as nitrogen, it is below the EPA MCL of 10 mg/L, but it is close enough that you should read the units carefully and stay on top of testing. Colorado State University Extension says seasonal variation happens, and high or borderline-high results may call for retesting every 3 to 6 months. If a baby under 6 months will be using the water, ask your local health department how they want you to handle a result near the limit. (epa.gov)

Should I test after heavy rain or flooding?

Yes. EPA says to test wells after flooding, especially if floodwater covered the well. CDC also says to test if there are problems near the well such as flooding or land disturbances. (epa.gov)