Nitrite rarely shows up in groundwater because it usually changes into nitrate in the environment. Nitrate is mainly used in fertilizers to help plants grow, while nitrite is used to cure meats. Labs usually test for nitrate and nitrite together, and the results are labeled as nitrate+nitrite as N.
- The safe level for nitrite-N in drinking water is 1.0 mg/L.
- The safe level for nitrate-N is 10 mg/L.
- Natural nitrate-N levels are usually less than 4 mg/L.
- If the level is over 4 mg/L, it might mean nitrate is getting into the groundwater from land use or septic systems.
- Levels over 8 mg/L are close to the health limit and should be watched closely, especially if a baby under 1 year old is drinking the water.
- Levels over 10 mg/L are unsafe, and you should stop using the water for babies or people with heart problems until you find the source of the contamination.
The biggest risk is for babies under 6 months old. In their bodies, nitrate turns into nitrite, which can block oxygen from being carried in the blood. This can cause "blue baby syndrome" (methemoglobinemia), where the skin turns blue or gray, especially around the mouth. This is an emergency and needs immediate medical care.
Nitrate is naturally found in soil and water in small amounts (less than 4 mg/L). However, contamination can come from septic systems, garbage dumps, fertilizers, manure, and decaying plants. When nitrate gets into groundwater, it’s often a sign that pollution is reaching the water supply.
How to Collect a Water Sample:
- Get a 250 mL neutral sampling bottle from the Department.
- Use a non-swivel faucet and remove the aerator.
- Let cold tap water run for 3–5 minutes to flush the pipes.
- Take off the bottle cap and fill the bottle to the neck.
- Put the cap back on tightly to prevent leaks.
- One bottle can be used to test for both nitrate and nitrite from the same location.
Filling Out the Form:
- Provide your mailing address, email, and phone number.
- Write down the date and time you collected the sample, the sample site information, and the type of water (e.g., well, surface water). For private wells, write "PRIVATE."
- Record the water temperature and chlorine levels (if you know them).
Submitting the Sample:
- Drop off the sample at the Department the same day you collect it. The test must start within 48 hours, so it needs to be submitted on time to stay valid.
Additional Information
Lead can sometimes be found in natural water, but it usually gets into drinking water from plumbing materials. Lead can come from old pipes, solder, and fixtures, especially if the water is corrosive. Things like low pH or dissolved oxygen in the water can cause lead to leach into the water.
Older homes often have lead pipes, and lead solder was commonly used to connect copper pipes until it was restricted in the 1980s. Lead in water cannot be seen, smelled, or tasted. If you think your water may contain lead, test the first water drawn from the tap after it hasn’t been used for 12 hours.
The U.S. Environmental Protection Agency (EPA) has set a safe drinking water limit for lead at 0.015 mg/L. Higher levels of lead can damage the kidneys, raise blood pressure, and harm the brain. Lead is especially dangerous for children, as it can cause delays in physical and mental development.
If you have questions about copper in drinking water, visit www.larimer.gov/copper.
How to Collect a Water Sample for Metals Testing:
- Get a 1-liter sampling bottle from the Department.
- Let the water sit in the pipes overnight without using the tap. Collect the sample first thing in the morning, without flushing the pipes.
- Remove the faucet aerator.
- Take off the bottle cap and fill the bottle to the neck.
- Put the cap back on tightly to prevent leaks.
Filling Out the Form:
- Provide your mailing address, email, and phone number.
- Write down the date and time you collected the sample, the sample site information, the type of water (e.g., well or surface water), and the water temperature (if known). For private wells, write "PRIVATE."
Submitting the Sample:
- Submit the sample to the Department for testing.
The Larimer County Department of Health and Environment does not conduct water testing for Uranium. Please inquire with the Weld County Laboratory for testing water samples for Uranium.
