Private Well Testing

At a minimum, you should test your private drinking water supply for coliform bacteria, nitrate and nitrite, and manganese. These contaminants are the common indicators used to provide basic information on drinking water safety. It’s easy and inexpensive to test for these contaminants. When any of them are present above the Environmental Protection Agency’s maximum contaminant levels (MCL) or health advisory level, you should not drink or consume the water without proper treatment.

We also recommend that every private well have at least one arsenic test performed so that the well user understands if arsenic is an issue with the water supply. More information on arsenic can be found on the State Hygienic Laboratory Arsenic Fact Sheet.

You may want to test for pesticides and other farm related chemicals if you obtain your water from a shallow well or your well is old, or if you obtain your water from a well finished in the shallower Karst bedrock regions of the state.

Pesticides are mostly modern chemicals that are used to control weeds and insects, and improve crop and turf production. They are applied on farms and in communities. You likely have a number of pesticides that you use routinely in and around your home. Atrazine is one of the most commonly found pesticides discovered during well water analysis. You can learn more about Atrazine in drinking water and health concerns that may be attributed to this chemical by visiting the CDC Atrazine Information web page. For more information on specific pesticide well water testing you may want to consider, please contact the State Hygienic Laboratory at the University of Iowa, 800-421-4692.

There are a number of other contaminants that you may want to test for based on your location in the state, the location of the well, the aquifer supplying your water, the age of the well (based on construction standards), and the land use or land history nearby your well. Contaminants like nitrate, arsenic, fluoride, radium, and lead are naturally occurring in some aquifers and may require specialized water treatment to reduce or eliminate the exposure risk. Certain locations may be susceptible to contamination from things like Volatile Organic Compounds (VOCs) such as gasoline, plastics, adhesives, dry-cleaning fluids, refrigerants, paints and solvents; animal waste like manure, carcasses and compost, or a number of emerging contaminants that may be linked to our modern lifestyle and activities.

These contaminants can end up in the groundwater due to local use and application, improper mixing, handling and storage, improper disposal, accidental spills, poor well construction, improperly abandoned wells, or the lack of natural protections in the local geology that normally provide protection to the local aquifers. If the natural protective features and barriers are not present in your region, the aquifers are more susceptible to contamination and you should test your water more often.

In the northeast region of Iowa, Karst bedrock features can allow surface water immediate access to the shallow groundwater. This makes the shallow groundwater more susceptible to surface contaminants. Wells in this part of the state require more stringent standards for well construction, increased water quality monitoring and increased maintenance of any drinking water treatment devices needed. For additional information on Karst terrain and water wells, please view our water wells in Karst areas web page.

If your water supply lacks adequate protections, is in poor repair, or utilizes an aquifer that interacts with surface water or very shallow groundwater, you should be especially aware of water borne diseases. Bacteria, viruses and protozoa are microorganism groups that contain pathogens that can cause waterborne diseases. For additional information on water borne diseases please see the Centers for Disease Control, Iowa Department of Public Health or your local county environmental health office.

Some private water systems may have corrosion issues that create the potential to release lead from the home’s plumbing into the water in the pipes. Corrosion in house plumbing can be described as a dissolving or wearing away of metal caused by a chemical reaction between water and your plumbing. There are a number of factors involved in the extent to which lead enters the water, these include:

• the chemistry of the water (acidity and alkalinity) and the types and amounts of minerals in the water,
• the amount of lead it comes into contact with,
• the temperature of the water,
• the amount of wear in the pipes,
• how long the water stays in pipes, and
• the presence of protective scales or coatings inside the plumbing materials.

We recommend that private water systems have at least one lead test performed to help determine if corrosion may be an issue with the plumbing. Additional testing may be required if you change your water source or your method of water treatment.

For advice on what your well should be tested for based on your well location and aquifer please contact your local county environmental health office, the State Hygienic Laboratory, the Iowa Department of Public Health or the Iowa DNR.