Drinking Water - Part 2

Drinking Water From Household Wells

If your family gets drinking water from your own well, do you know if your water is safe to drink? What health risks could you and your family face? Where can you go for help or advice?

This section helps answer these questions. It gives you general information about drinking water from home wells (also considered private drinking water sources). It describes types of activities in your area that can create threats to your water supply. It also describes problems to look for and offers maintenance suggestions.

All of us need clean water to drink. We can go for weeks without food, but only days without water. Contaminated water can be a threat to anyone's health, but especially to young children.

About 15 percent of Americans have their own sources of drinking water, such as wells, cisterns, and springs. Unlike public drinking water systems serving many people, they do not have experts regularly checking the water's source and its quality before it is sent through pipes to the community.

To help protect families with their own wells, almost all states license or register water-well installers. Most also have construction standards for home wells. In addition, some city and county health departments have local rules and permitting. All this helps make sure the well is built properly. But what about checking to see that it is working correctly and the water is always healthy to drink? That is the job of the well owner, and it takes some work and some knowledge.

  • What Is Ground Water And How Can It Be Polluted?

Ground water is a resource found under the earth's surface. Most ground water comes from rain and melting snow soaking into the ground. Water fills the spaces between rocks and soils, making an "aquifer". About half of our nation's drinking water comes from ground water. Most is supplied through public drinking water systems. But many families rely on private, household wells and use ground water as their source of fresh water.

Ground water - its depth from the surface, quality for drinking water, and chance of being polluted - varies from place to place. Generally, the deeper the well, the better the ground water. The amount of new water flowing into the area also affects ground water quality.

Ground water may contain some natural impurities or contaminants, even with no human activity or pollution. Natural contaminants can come from many conditions in the watershed or in the ground. Water moving through underground rocks and soils may pick up magnesium, calcium and chlorides. Some ground water naturally contains dissolved elements such as arsenic, boron, selenium, or radon, a gas formed by the natural breakdown of radioactive uranium in soil. Whether these natural contaminants are health problems depends on the amount of the substance present.

In addition to natural contaminants, ground water is often polluted by human activities such as:

  • Improper use of fertilizers, animal manures, herbicides, insecticides, and pesticides.

  • Improperly built or poorly located and/or maintained septic systems for household wastewater.

  • Leaking or abandoned underground storage tanks and piping Storm-water drains that discharge chemicals to ground water Improper disposal or storage of wastes.

  • Chemical spills at local industrial sites.

Suburban growth is bringing businesses, factories and industry (and potential sources of pollution) into once rural areas where families often rely on household wells. Growth is also pushing new home developments onto the edge of rural and agricultural areas. Often municipal water and sewer lines do not extend to these areas. Many new houses rely on wells and septic tanks. But the people buying them may not have any experience using these systems.

  • Most U.S. ground water is safe for human use. However, ground water contamination has been found in all 50 states, so well owners have reason to be vigilant in protecting their water supplies. Well owners need to be aware of potential health problems. They need to test their water regularly and maintain their wells to safeguard their families drinking water.


  • Where Do Ground Water Pollutants Come From?

Understanding and spotting possible pollution sources is important. It's the first step to safeguard drinking water for you and your family. Some threats come from nature. Naturally occurring contaminants such as minerals can present a health risk. Other potential sources come from past or present human activity - things that we do, make, and use - such as mining, farming and using chemicals. Some of these activities may result in the pollution of the water we drink.

Several sources of pollution are easy to spot by sight, taste, or smell. However many serious problems can only be found by testing your water. Knowing the possible threats in your area will help you decide on the kind of tests you need.

  • Quick Reference List of Noticeable Problems
  • Visible

  • Scale or scum from calcium or magnesium salts in water

  • Unclear/turbid water from dirt, clay salts, silt or rust in water Green stains on sinks or faucets caused by high acidity Brown-red stains on sinks, dishwasher, or clothes in wash points to dissolved iron in water

  • Cloudy water that clears upon standing may have air bubbles from poorly working pump or problem with filters.

  • Tastes

  • Salty or brackish taste from high sodium content in water

  • Alkali/soapy taste from dissolved alkaline minerals in water

  • Metallic taste from acidity or high iron content in water

  • Chemical taste from industrial chemicals or pesticides

  • Smell

  • A rotten egg odor can be from dissolved hydrogen sulfide gas or certain bacteria in your water. If the smell only comes with hot water it is likely from a part in your hot water heater.

  • A detergent odor and water that foams when drawn could be seepage from septic tanks into your ground water well.

  • A gasoline or oil smell indicates fuel oil or gasoline likely seeping from a tank into the water supply

  • Methane gas or musty/earthy smell from decaying organic matter in water Chlorine smell from excessive chlorination.

  • Note: Many serious problems (bacteria, heavy metals, nitrates, radon, and many chemicals) can only be found by laboratory testing of water.

  • What are Some Naturally Occurring Sources of Pollution?
  • Microorganisms: Bacteria, viruses, parasites and other microorganisms are sometimes found in water. Shallow wells - those with water close to ground level - are at most risk. Runoff, or water flowing over the land surface, may pick up these pollutants from wildlife and soils. This is often the case after flooding. Some of these organisms can cause a variety of illnesses. Symptoms include nausea and diarrhea. These can occur shortly after drinking contaminated water. The effects could be short-term yet severe (similar to food poisoning) or might recur frequently or develop slowly over a long time.

  • Radionuclides: Radionuclides are radioactive elements such as uranium and radium. They may be present in underlying rock and ground water. Radon - a gas that is a natural product of the breakdown of uranium in the soil - can also pose a threat. Radon is most dangerous when inhaled and contributes to lung cancer. Although soil is the primary source, using household water containing Radon contributes to elevated indoor Radon levels. Radon is less dangerous when consumed in water, but remains a risk to health.

  • Nitrates and Nitrites: Although high nitrate levels are usually due to human activities (see below), they may be found naturally in ground water. They come from the breakdown of nitrogen compounds in the soil. Flowing ground water picks them up from the soil. Drinking large amounts of nitrates and nitrites is particularly threatening to infants (for example, when mixed in formula).

  • Heavy Metals: Underground rocks and soils may contain arsenic, cadmium, chromium, lead, and selenium. However, these contaminants are not often found in household wells at dangerous levels from natural sources.

  • Fluoride: Fluoride is helpful in dental health, so many water systems add small amounts to drinking water. However, excessive consumption of naturally occurring fluoride can damage bone tissue. High levels of fluoride occur naturally in some areas. It may discolor teeth, but this is not a health risk.

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