Wells and Wellhead Protection: Testing

Well water quality can vary greatly. As groundwater moves downward through soil and rock formations, it dissolves minerals and many other compounds. Much of Nebraska's groundwater is considered to be “hard” water because it contains dissolved minerals. Calcium and magnesium are the two most common minerals, while iron and/or manganese are sometimes present, and the water in some areas of the state contains sulfate. While these are not considered health risks, they can be a nuisance, causing staining and mineral deposits (lime build-up). In addition they can make water less palatable.

Other dissolved minerals may present a health risk. Two minerals known to be present in some Nebraska groundwater are arsenic and uranium. Water from some wells in eastern Nebraska may contain extremely high levels of total dissolved solids.

Pathogenic bacteria, viruses, and microbial organisms in water can be a health risk. Natural treatment occurs as water moves downward through layers of soil, sand, and gravel. Due to this natural treatment process, bacteria and other pathogens are not likely to move through the soil layers into the groundwater from deep, drilled wells. Bacteria could move into well water from shallow wells, older water systems, dug wells, systems with casings or caps that are not water-tight, or any well that is inundated by flood waters or surface runoff. More information on contaminated runoff is presented on the Lawns & Landscapes pages of this Water Web site.

Excessive concentrations of nitrate-nitrogen in well water can be a health risk, especially for infants and pregnant women. Nitrate-nitrogen may result from point sources like sewage disposal systems and livestock facilities or from nonpoint sources like fertilized cropland, parks, golf courses, lawns, and gardens.

Testing Well Water for Drinking Water Use:water sample bottle

Water from public drinking water wells is regulated and required to be frequently tested for quality. Water from private drinking water wells is not regulated. It's a good idea to test the water from any new private drinking water well. At a minimum, the water should be tested for bacteria and nitrate. Additional tests might be requested if a specific contaminant is suspected. In addition, testing a private water supply annually for bacteria and nitrate is recommended. Many Nebraska laboratories offer water testing services. More information and resources may be found on the Drinking Water Testing pages within this Water Web site.

Testing Well Water for Irrigation:

The quality of irrigation well water is also not regulated, but should be tested periodically. Nitrate-nitrogen commonly occurs in irrigation well water, and by knowing the amount present, it can be accounted for thus potentially reducing fertilizer input costs. Other compounds that could adversely affect crop yields may be present in the irrigation well water. Testing can identify these.

Testing Well Water for Livestock Use:

Water is the single most important nutrient for livestock, making up 98% of all molecules in the body. Research trials have documented reduced animal performance and in some cases death due to water contamination. Total dissolved solids over 7,000 ppm should be avoided if possible, especially for pregnant or lactating cows. Water containing over 220 ppm N0 3 can put cattle at risk for death loss. It has been reported that water containing over 2,600 ppm sulfates reduced animal performance. Providing clean, fresh water to livestock is a best management practice that can improve performance and livestock health. More on livestock and poultry environmental concerns


Information presented within this section of this Water Web site has been reviewed by University of Nebraska-Lincoln Wellhead Management and Drinking Water team members David Shelton, Sharon Skipton, Bruce Dvorak, Wayne Woldt, and Jan Hygnstrom.