Click below to read more information about specific contaminants that can be found in Wisconsin’s drinking water.


Arsenic is an element that occurs naturally in soil and bedrock formations. Traces of arsenic are also found in groundwater, lakes, rivers and ocean water; oftentimes showing up in well water. Foods like fruits, vegetables and seafood can also contain arsenic. Toxic levels of arsenic have been linked to specific cancers (skin, bladder, prostate and lung), rough skin and numbness in the hands and/or feet, stomach pain, nausea, diahrea and/or depression.

SAFE DRINKING WATER STANDARD:     10 ppb (parts per billion)


Most bacteria entering the ground surface along with rainwater or snowmelt are filtered out as the water seeps through the soil. Several strains of bacteria can survive a long time and find their way into the groundwater by moving through coarse soils, shallow fractured bedrock, quarries, sinkholes, inadequately grouted wells or cracks in the well casing. Insects or small rodents can also carry bacteria into wells with inadequate caps or seals.

Most common water based bacterium found in water includes: coliform, e.coli, legionella and pseudomonas.


Chromium is a metallic element found in nature, present in rocks, soil, plants and animals. It is commonly used in industrial processes such as steel making, leather tanning, paints, dyes, and wood preservatives. An excess of Chromium 6, which is a carcinogen, in drinking water can lead to reproductive health issues in men and women, can lead to eye, skin and respiratory irritation, and also have an adverse impact on the liver and kidneys.

SAFE DRINKING WATER STANDARD:     100 ppb (parts per billion)


Copper is a reddish metal that occurs naturally in rock, soil, water, sediment, and air and is commonly used to make pennies, electrical wiring, and water pipes. Copper compounds are also used as an agricultural pesticide and to control algae in lakes and reservoirs. Immediate effects from drinking water which contains elevated levels of copper include vomiting, diarrhea, stomach cramps, and nausea. Long-term exposure (more than 14 days) to very high levels of copper in drinking water has been found to cause kidney and liver damage in some people. Children under one year of age are more sensitive to copper because it is not easily removed from their system. 

SAFE DRINKING WATER STANDARD:     1.3 mg/L (miligrams per liter)


Iron is one of the most common elements found in nature, making up roughly 5% of the Earth’s crust. When rainfall seeps through the soil, the iron in the earth’s surface dissolves, causing it to go into almost every natural water supply, including well water. Both soluble and insoluble iron can be present in drinking water, either settling at the bottom of poured glass or interspersed throughout the volume of water, creating a red or yellow tint to the liquid. Both types can create serious taste and appearance problems for the water user.

SAFE DRINKING WATER STANDARD:     0.3 mg/L (miligrams per liter)


Lead is a toxic metal which has been used in the construction of most household plumbing systems in Wisconsin. Water within the plumbing system will continuously dissolve the lead it contacts. Lead absorbed by the lungs and the digestive tract from all sources enters the bloodstream, where it distributes to all tissues of the body. Excessive levels of lead can damage the brain, kidneys, nervous system, red blood cells and reproductive system. The degree of harm is directly related to the level of lead in the blood.

SAFE DRINKING WATER STANDARD:     15 ppb (parts per billion)


Nitrate  is a compound made up of nitrogen and oxygen. It is formed when nitrogen from ammonia or other sources combines with oxygen in water. Nitrate is naturally found in plants and in vegetables at varying concentrations. It is often in groundwater depending on the amount of fertilizer and manure applied to crop fields. Some researchers suspect that consuming nitrate-contaminated water may increase the risk of thyroid disease, diabetes, and certain types of cancer. Pregnant mothers and infants are at an especially high risk for nitrate poisoning if not routinely monitored.

SAFE DRINKING WATER STANDARD:     10 ppm (parts per million)


Most private wells provide a clean, safe supply of water; however, contaminants can pollute private wells, and unfortunately you cannot see, smell or taste most of them. Consequently, you should test your water on a regular basis. The decision on what to test your water for should be based on the types of land uses near your well.

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6905 Venture Circle, Weston, WI 54476

(800) 932 - 2216