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Private Wells Testing

If you have a private well, regular water quality testing is very important. Many contaminants cannot be identified by taste or odor, making it difficult for homeowners to know if the water quality of their well has changed. The Environmental Protection Agency (EPA) does not regulate private wells and many states and towns do not require periodic sampling of private wells after they are initially installed. This puts the responsibility on homeowners to periodically test their well water for contamination.

Common water quality tests check for microorganisms such as E. Coli, and elevated chemical levels of nitrates, arsenic, uranium, lead, and fluoride by taking a water sample from your well or from your drinking water source in your home. If your well water smells, it may taste and look fine, but it should be tested. Often, microorganisms and chemicals go unnoticed and the only way to find these contaminants is through testing. If elevated levels of these naturally-occurring and man-made contaminants, as determined by the EPA Safe Drinking Water standards, are in your drinking water, they can cause abdominal cramping and diarrhea or other health problems.

Where To Get Well Water Tested

About 13 percent of New Mexicans receive their water from private wells, which are not routinely tested. There are some options for New Mexicans to test their water. They can take their water to certified laboratories or take advantage of the opportunities available through state-sponsored water fair community events and individual testing by the New Mexico Environment Department.

  • Community Testing Events - Well Water Test Fairs To support well owners in New Mexico, the state Department of Health supports the state Environment Department's Water Test Fair program, which periodically offers testing for constituents which may be naturally occurring or result from sources including fertilizer, animal waste, septic tanks, and refuse dumps. Free testing for: arsenic, fluoride, sulfate, nitrate, iron, electrical conductivity, and pH. See the link in the Associated Topics section below for an event near you.
  • Individual Testing Opportunities - Onsite Wastewater Bureau The New Mexico Environment Department (NMED), Liquid Waste (septic tank) Program provides free testing for nitrate, fluoride, and iron for private well owners at local NMED field offices.
  • Certified Drinking Water Laboratories For tests not available through free testing opportunities, it is recommended private well owners test their drinking water through labs that have applied for New Mexico certification and have been approved by the New Mexico Environment Department Drinking Water Bureau. Check with laboratories for pricing.

What to Test For and When To Test

Make your drinking water quality a health priority for you and your family by testing your water. The table above provides New Mexico Private well users common testing recommendations, and where each type of test is available.

Drinking well water recommended testing schedule.

Every Year: Bacteria and nitrates

Checking these yearly is a good indicator if your water quality has degraded. This may mean your well casing has cracked or your water has been polluted by animal or human waste. The best time to test is in spring.

Periodically: Other chemicals

Test at least once for arsenic, cadmium, fluoride, iron, lead, manganese, pH and hardness, sulfate, and uranium. If you live in an area that may be subject to industrial pollution, or near a mine or mill site, test periodically for contaminants of concern, such as arsenic and uranium for many parts of the state.

Other harmful chemicals that you should test for will depend on where your well is located on your property and whether you live in an urban or rural area. These tests could include testing for lead, mercury, radium, and atrazine, or other pesticides.

Testing can be done between scheduled times for different reasons.

Other reasons to test:

  • There are known problems with well water in your community.
  • Problems near your well (i.e., flooding, land disturbances, or nearby waste disposal sites).
  • You replace or repair any part of your well system, such as a pump.
  • Someone in the home is expecting a baby or is nursing.
  • The water changes in smell, taste or color.
  • The well runs dry and then comes back.
  • A spill of chemicals or fuels occurs near your well.
  • You put in a treatment system to fix a water quality problem.
  • New agricultural activities near your well.
  • You just installed the well or purchased property or a home with a well.

What do the Water Test Results Mean? Choosing a Treatment Option

After you test your water, it is important to understand what the results mean. The table above provides a simple guide to understanding your test results and some treatment options. Use the water quality interpretation tool from Colorado State University, to find out what your lab results mean (link in Downloads and Resources). Choose the US option. The National Groundwater Association provides more information about interpreting your water test results.

This information can help you select an appropriate water treatment system if needed. If test results show that your drinking water contains contaminants at levels above the safe limit, you can improve the quality with treatment. An appropriate water-treatment system or use of an alternative source of drinking water, such as bottled water is recommended.

Water test results interpretation table