Nitrate and Drinking Water from Private Wells

What is nitrate?

Nitrate is a compound that is formed naturally when nitrogen combines with oxygen or ozone. Nitrogen is essential for all living things, but high levels of nitrate in drinking water can be dangerous to health, especially for infants and pregnant women. Nitrates are also made in large amounts by plants and animals, and are released in smoke and industrial or automotive exhaust.

How can I be exposed to nitrate?

Adults are mainly exposed to nitrate through foods. The main nitrate exposure for infants is formula and other baby foods prepared with contaminated well water.

Where and how does nitrate get into drinking water?

Nitrate can occur naturally in surface and groundwater at a level that does not generally cause health problems. High levels of nitrate in well water often result from improper well construction, well location, overuse of chemical fertilizers, or improper disposal of human and animal waste. Sources of nitrate that can enter your well include fertilizers, septic systems, animal feedlots, industrial waste, and food processing waste.

What is methemoglobinemia and what are the symptoms?

Methemoglobinemia is a blood disorder that can be caused by having too much nitrate in your body. In babies less than 6 months of age, high levels of nitrate in the body will prevent the blood from delivering oxygen effectively to different parts of the body. As a result, the infant may have blueness around the mouth, hands, and feet (hence the name "blue baby syndrome"). This blue color does not necessarily mean that the infant is having breathing problems. However, without treatment and the removal of nitrate from drinking water, the condition could worsen and affect the baby's breathing. Other signs of blue baby syndrome include vomiting and diarrhea.

Pregnant women do not tolerate nitrates well. Some research studies have shown that if a pregnant woman drinks water contaminated with nitrate, it can affect the health of her baby. Women who are nursing are also advised not to drink water containing high levels of nitrates, as the nitrates may be passed to their infants. However, the amount of nitrate in breast milk is generally very low and no cases of methemoglobinemia have been linked to breast milk use.

Healthy adults with elevated levels of methemoglobin may not have obvious symptoms. However, some signs of methemoglobinemia include shortness of breath, headache, fatigue, dizziness, and changes in mental status. If levels get extremely high, it can result in loss of consciousness, seizures, and coma.

What should I do if I have concerns about methemoglobinemia?

See your health care provider immediately to discuss your concerns. Treatment is available.

How is methemoglobinemia diagnosed?

A simple and quick finger-prick blood test can be used to diagnose methemoglobinemia.

What is the treatment for nitrate exposure?

Severely affected infants may need treatment. Consult with your health care provider. For most people, changing your drinking water source can prevent any negative health effects or the need for treatment. The new water source should have less than 10 milligrams of nitrate-nitrogen per liter.

How do I remove nitrate from my drinking water?

Nitrate may be successfully removed from water using treatment processes such as ion exchange, distillation, and reverse osmosis. Contact your local health department for recommended procedures.

NEVER heat or boil your water to remove nitrate. Because some of the water will evaporate during the boiling process, the nitrate levels of water can actually increase in concentration if the water is boiled. Mechanical filters or chemical disinfection, such as chlorination, DO NOT remove nitrate from water.

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