Brown winter in Spring Green
The problem of ground water pollution is wide spread throughout Wisconsin and midwest due to large scale Ag operation. These operations tend to produce more nitrates than the crops that they can grow use and over application of waste products is common. Another concern when high nitrates are present in ground water is the presents of other inorganic chemicals (Ag related). These could pose a greater health issues then the nitrates. Until the State becomes more proactive in protecting our groundwater resources the problem will continue to increase.
Yes the EPA MCL for nitrate in drinking water is 10 mg/L, but numerous studies are showing any amount of nitrate-nitrogen in drinking water is hazardous ( see: http://ehp03.niehs.nih.gov/search/simpleSearch.action?sort=&query=Nitrates+in+drinking+water&ELocationId=&startPage=1&id=&filterArticleType=&pageSize=10&unformattedQuery=&filterKeyword=&filterSubjects=&volume=&filterJournals=)
I bet the lack of rain this summer is exacerbating the problems with groundwater. There is no natural cleansing and leaching.