Nitrates and Nitrites in Drinking Water

Nitrates and Nitrites in Drinking Water

Nitrogen can take different forms in nature and is important for life in both plants and animals. The most common form of nitrogen found in well water is nitrate. Wells with high levels of nitrates are more likely to be privately owned or shallow and affected by human activity.

Health Concerns: Are nitrates or nitrites harmful to my health?

There are two health concerns when drinking water with high levels of nitrates or nitrites.

The first is risk of “blue baby syndrome,” also called methemoglobinemia:

  • Poisoning can occur when babies drink formula made with nitrate- or nitrite- contaminated tap water.
  • The baby’s blood is less able to carry oxygen due to poisoning.
  • Affected babies develop a blue-gray color and need emergency medical help immediately.
  • Babies under six months of age are more at risk.

The second is the potential formation of chemicals called nitrosamines in the digestive tract. Nitrosamines are being studied for long-term links to cancer. No standards have been set for this yet.

Source: How do nitrates and nitrites get into my water?

Nitrate contamination of water usually comes from fertilized agricultural fields, septic system failures, or compost piles that are too close to wells.

Learn how to take care of your septic system

Testing: How do I know if nitrates or nitrites are in my water?

You cannot see, smell or taste nitrates or nitrites. Testing is the only way to know if nitrates or nitrites are in your drinking water. The Health Department recommends testing your private water source for nitrates every five years.

If human or animal waste contaminates a well, nitrites will be detected first but will quickly convert to nitrates. Therefore, most well water tests are done for nitrates.

The drinking water standard for nitrates in water is 10.0 mg/L and nitrites is 1.0 mg/L. The Health Department recommends taking action to remove or lower nitrates if levels are above 5.0 mg/L.

Due to the COVID-19 response, the Vermont Department of Health Laboratory has suspended drinking water testing. You can order an inorganic chemical test kit from an alternate certified drinking water lab.

Test Results: Is my result a problem?

If your final result for nitrate is more than (>) 10 mg/L, the level is over the health standard and treatment is recommended.

If your final result for nitrate is more than (>) 5 mg/L, the level is approaching a level that is unsafe for babies under six months old to consume. The contamination may be coming from sources such as runoff from farm fields, manure piles, septic systems or compost piles. Consider addressing these sources.

If your final result for nitrite is more than (>) 1 mg/L, the level is over the health standard and treatment is recommended.

Treatment Options: Can I remove or lower the levels of nitrates in my water?

Nitrate levels can be lowered in drinking water with treatment. Re-test for nitrates after any treatment system is installed to make sure levels are below the drinking water standard.

Anion Exchange
Anion exchange is a treatment like water softening, but uses a different media that exchanges the nitrates for chloride. This is installed as a whole house system (point-of-entry or POE).

Reverse Osmosis
This system uses a synthetic membrane that allows water to go through but leaves nitrates behind. The membrane is continually rinsed. This system is typically installed under a kitchen sink (point-of-use or POU), but can also be installed POE system. Install a system with a National Sanitation Foundation (NSF/ANSI) Standard 58 Certification. Search for an NSF/ANSI-certified reverse osmosis treatment system

Financial Assistance: Is there funding available to help me pay for my water system or treatment?

Vermont Wastewater and Potable Water Revolving Loan Fund
This program, also known as the On-Site Loan Program, is available to certain Vermont residents for the repair or replacement of failed water supply and on-site wastewater systems. The On-Site Loan Program is funded and administered by the Agency of Natural Resources, Department of Environmental Conservation with loan underwriting and servicing provided by the Opportunities Credit Union in Winooski. Your drinking water supply has to be a failed system and you must be living in the residence on a year-round basis to be eligible. The family income cannot exceed 200% of the state median household income. For more information about eligibility and how to apply, call the On-Site Loan Program at 802-461-6051.

The NeighborWorks Alliance of Vermont
The NeighborWorks Alliance is made up of five local organizations offering full affordable housing services for income-eligible individuals. You may qualify for help from this program if you need money to install a water treatment system, drill a well, or repair or replace your septic system. For more information on eligibility, contact the local NeighborWorks Group in your region.

Single Family Housing Repair Loans and Grants
This program offers loans and grants to existing homeowners for well construction, repair and sealing. It's administered by the Rural Development office of the U.S. Department of Agriculture. The program is for low-income families who live in a rural area or a community with a population of 25,000 or less. The family income cannot exceed 50% of the median county income. Individuals who are 62 years of age or older may qualify for a grant or a combination of a loan and a grant. Younger applicants are eligible only for loans.

Burlington, South Burlington, Essex Junction, Winooski and parts of Colchester are ineligible for the program. Even if your property is in an eligible area, your eligibility is still subject to income limits. For more information or to find out if your property is in an eligible area, call the USDA Rural Development Office at 802-828-6022.