Even if you don’t have any immediate concerns, you need to know what is in your well water. Have your water tested regularly and know how to interpret the results. Bacteria, arsenic, radon, barium, iron and manganese should be regularly tested for, because they can be very dangerous.

Let’s look at these things one by one.


Most of the bacteria that is in water is not harmful and does not cause disease. But those that do are called pathogens. Pathogens such as fecal coliform and E-coli indicate that the water source is contaminated. Pathogens can enter the well through runoff from woodlands, pastures, or feedlots, or from septic tanks and sewage. Be aware that coliforms may be present if there have been significant environmental changes in the area recently.


Arsenic is naturally occurring in the rocks and the soil, and can enter the well water from natural deposits, or from pollution. It can remain in water for a long time. Naturally occurring arsenic gets into water when ground levels drop. Arsenic is also used in industry, as a by-product of copper smelting, coal burning or mining. It is combined with other elements to make chemicals, pesticides, or fertilizers. If your test for arsenic in the well is positive, the arsenic must be removed. Boiling the water will not help.


This gas that has no color, odor, or taste. It comes from the natural buildup of uranium in rocks and soil and it can dissolve into the water. If the groundwater in your area is high in radon it can get into your private well and then be released back into the air in your home as radon gas. Too much of this gas can be harmful, and contributes to the development of lung cancer


Barium is a soft, silver white metal. It exists in nature and is often combined with other elements such as sulfur, carbon, or oxygen. It is also used in industry for oil and gas drilling, for x-ray diagnostics, and as an agent in plastics, ceramics, or fertilizers or pesticides. Barium may leach into the water or soil, but not in amounts expected to do harm. Very large amounts, however, can cause cramps, vomiting, and even death.


This metal is naturally present in water as iron is one of the earth’s most plentiful resources. It exists in two forms: in water as a soluble ferrous iron, or as insoluble ferric iron. The ferrous iron is clear and colorless because it is completely dissolved, but ferric iron, when oxidized, is a cloudy reddish brown, which is not aesthetically pleasing and gives the water an unpleasant taste.


Like iron, manganese is naturally occurring in the soils and rocks. It is beneficial when found in foods such as grains and vegetables, but it is not wanted in water. It can bring an unpleasant color, odor, or taste to the water.

Test Your Well Water

If you use water from a private well, being aware of what is in the water should be your main concern. Test the water at least annually, but also if there have been significant changes to your area in the past months. Significant weather incidents, health concerns or even new industry in the area can change the composition of the groundwater.