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Regular maintenance of wells important for safe water

Wisconsin State Farmer

ST. CROIX COUNTY - In St. Croix County there are approximately 16,000 private drinking water wells that serve nearly 43,000 rural residents. If you are one of those private well owners, you probably don't have an owner's manual that goes with your well.

A two-year study found that about 380 residents in Kewaunee County are at risk of contracting a stomach parasite due to fecal microbes in some wells.

Whether you moved out to the country and are a first time owner of a water well or you have relied on a rural water well most of your life, you may not realize wells need testing and maintenance to prevent or address problems. Unfortunately, most people have no idea about what they should be doing to keep their rural well functioning correctly.

There are four general steps to taking care of your well:

  • Maintain a well record, sometimes called a well log, containing documents related to the well construction, water testing results, inspections, maintenance and repairs.
  • Test annually for bacteria, nitrates and chlorides using a state certified laboratory. For more information on well testing options and costs go to Community Development Drinking Water Program.
  • Hire a certified professional to do a well inspection, including pump, storage tank, pipes, valves and water flow. This should be done every 10 years for new wells, or as soon as possible if you have no inspection history. A list of certified inspectors is available at
  • Protect your well’s refill/recharge zone and everyone’s water through proper disposal of hazardous products, septic system maintenance and avoiding over-application of pesticides and fertilizers.

Well Logs

Homeowners should keep track of some basic information about their well; the location, construction details and date, depth, casing depth and general water-table geology. Since 1936, well construction reports have been required for all wells installed by licensed well drillers. Drillers are responsible for completing and submitting well records to the Wisconsin Department of Natural Resources. A homeowner who doesn’t have a copy of their well record should contact the well driller, builder/developer or visit the following website

If your water supply became impacted by contamination or drought conditions, information about the well depth, casing depth and pump type are valuable details used to determine the next steps. For example, wells can be drilled deeper, mechanical components can be upgraded and replaced, pumps can be lowered, well and well components can be disinfected or a water treatment system can be installed.

Well Testing 

An annual well-water test should include coliform bacteria, nitrate and chlorides; the cost is less than 14 cents per day or $50 per year and covers the most common health-related concerns. In addition, any source of drinking water should be tested any time there is a change in taste, odor or appearance, or anytime a water supply system is serviced.

If you have aesthetic problems related to taste, odor, staining or color of your water, then test for iron, manganese and sulfate. Shallow wells, those less than 50 feet deep, and shallow-cased wells, those not cased to the depth of the water table, have a greater risk of contamination.

Once you have your water tested, examine the test results carefully to understand what contaminants, if any, exist in your water, where they come from, and what risks they pose. A water test only provides a “snapshot” of one day’s water quality. If a well tests positive for bacteria after two separate tests, then your next step is to have the entire well system inspected and disinfected by a certified professional.

Well Inspection

Small problems can often be identified through regular maintenance to prevent expensive and inconvenient problems. This is similar to performing routine maintenance and performance checks on a motor vehicle to find engine, brake, exhaust, etc. problems before they lead to a more serious break down. Do not become stranded without water over the relatively small cost of an annual service call—the cost of a repair call could be much higher.

Surface water may carry contaminants including bacteria, nitrates, and chlorides. Homeowners should periodically check the well cover or well cap on top of the casing (well) to ensure it is in good repair and prevent contaminants from entering the well. They should also be aware that low or no-water usage for extended periods can lead to stagnant water and bacteria growth in the well or its components.

A homeowner’s regular well maintenance checklist should include contacting a licensed well driller, pump installer, or well inspector for periodic well inspections; some inspections will include water testing. The inspection should look for missing, cracked or damaged well cap, improperly functioning pump and possible sources of bacterial contamination.

Well Recharge Protection

Like many people you may remember as a child being told “the solution to pollution is dilution” we now know dilution doesn’t solve the contamination is just delays addressing the problem. Most residential wells have recharge or refill zone drawing water that entered the ground within a few hundred feet or a few miles of the well. Contaminants washed into the ground by rainwater or snowmelt are usually filtered out as the water seeps through the soil, but they sometimes percolate down through the soils and bedrock into the underlying aquifers or enter the well-water supply through cracks in the well casing, poorly-sealed caps, or underground pressure tanks.

Some property owners can contaminate their own wells through improper usage and disposal of hazardous materials or wastes. Dumping medications down the sink or toilet, poorly maintained septic systems, residential and agricultural fertilizers and pesticides, livestock or other animal waste runoff, road salts, chemical spills and flooding/storm water runoff can all be sources of well contamination.

We all know to handle hazardous materials carefully utilizing gloves, child safety caps, warning stickers, locked cupboards, etc. However, when hazardous materials such as fertilizers or pesticides are over applied by homeowners or agricultural producers, or when gasoline or oil spills occur, these chemicals can leach through the ground into your well-water supply.

Keep hazardous chemicals, such as paint, fertilizer, pesticides and motor oil away from your well, dispose of them properly at a Household Hazardous Waste Collection program. Utilize the free Take Back Drugs program to properly dispose of medications.

For more information on these programs and more ways to properly dispose handle and dispose of hazardous materials go to

Groundwater quality can change over time and a well that tests safe today could become contaminated. To ensure good water quality for the future, start taking care of your well today.

For more information about private well ownership visit