Well Water and Drinking Water Quality
About 20 percent of the population in New Mexico (or estimated 350,000 people) receive their water from a private well. According to the office of the state engineer, private wells use 11.6 billion gallons of water per year, which is estimated at about 10 percent of the drinking water usage in New Mexico. The water quality from private wells is not monitored or regulated by the EPA or the state. It is the responsibility of the home owner to ensure that their water is safe for human consumption.
About 10 percent of the United States population has their own sources of drinking water, such as wells, cisterns, and springs. Unlike public drinking water systems, drinking water quality from private wells is not regularly checked.
How can contaminants get into drinking water?
Most U.S. groundwater is safe for human use. However, elevated groundwater levels of contaminants have been found in all 50 states, so well owners have reason to be vigilant in protecting their water supplies. Drinking water can be contaminated by natural sources, like bedrock, or from man-made sources, like disinfection chemicals, agricultural run-off, or plumbing fixtures. Contamination can happen if there are new sources of contamination in the wells, reservoirs, lakes, or rivers or if there are problems with the water treatment system.
Levels of various naturally-occurring and man-made contaminants in New Mexico groundwater, including arsenic, uranium, manganese, nitrates, fluoride, sulfate, and bacteria might be elevated above the Environmental Protection Agency (EPA) Safe Drinking Water standards. Ongoing drought conditions and aquifer mining have raised further concern that increases in contaminants may occur in the absence of significant ground water recharge events.
Make sure your well water is healthy to drink: Tips for Well Owners (734.2 KB)
Protecting your drinking water
The U.S. Environmental Protection Agency's (EPA) rules that protect public drinking water systems do not apply to privately owned wells. As a well owner, it is up to you to make sure that your water is safe to drink. Well owners need to be aware that there are potential health problems from drinking water of poor quality. They should test their water regularly and maintain their wells to safeguard their families' drinking water.
To help protect families who own these wells, almost all states license or register water-well installers. Most also have construction standards for home wells. In addition, some city and county departments have local rules and permitting. All of these precautions help ensure that a well is built properly. However, the job of checking to see that the well is working correctly and that the water is always healthy to drink belongs to the well owner, and it takes work, knowledge, and resources.
The risk of having drinking water quality problems depends on how good a well is: how well it was built, where it is located and how well it is maintained. It also depends on the local environment, which includes the quality of the aquifer from which water is drawn (which can change over time) and human activities in the area that can affect the well water. Some questions to consider in protecting drinking water and maintaining a well are:
- What distance should a well be from sources of human wastes such as septic systems?
- How far should a well be from animal feedlots or manure spreading?
- How far should a well be from agricultural land where fertilizers, herbicides, or other pesticides are used?
- What are the types of soil and underlying rocks where the well will be?
- Does water flow easily or collect on the surface?
- How deep must a well be dug to avoid seasonal changes in groundwater supply?
- What activities in the area (e.g., farming, mining, industry) might affect the well?
- What is the age of the well, its pump, and other parts compared with their expected lifetimes?
- Is the water distribution system protected from cross connections and backflow?
Testing your Drinking Water
The best way to know if drinking water from a private well is safe to drink is by testing it. Common water quality tests check for germs such as E. Coli, and chemicals such as nitrates, arsenic, uranium, lead, and fluoride.
Drinking water quality is checked periodically in public/ community drinking water systems. If the tests show unhealthy levels of germs or chemicals, the community is alerted and the managers of the water system work to fix the problem. If your drinking water comes from a private well, you need to test the water periodically and fix any problems if the water is of poor quality.
If your well water smells, tastes and looks fine, you should still have it tested. Often germs and chemicals are unnoticed and the only way to find these is through testing. If germs are in your drinking water, they can cause abdominal cramping and diarrhea, for example.
Learn more about testing you well water.
If bacteria, parasites, and chemicals are in your well water, you can improve the quality with treatment. To make sure your water is safe for drinking, testing is your first step.
When test results show that your drinking water contains contaminants at levels above the safe limit, an appropriate water-treatment system or use of an alternative source of drinking water is recommended.
Learn about well water treatments options.
Get more resources for well owners.