Appleton has some of the best tasting drinking water in the country. We pay a price for it because it uses advanced and rather expensive technology, but the result is wonderful. Here are some details from Appleton's Water Treatment Facility page:

The City of Appleton recently completed construction of a new 24 million gallon per day (MGD) lime softening Water Treatment Facility. The facility was built to accommodate the growth of the community and to meet the new water regulations mandated by the Wisconsin Department of Natural Resources (WDNR) beginning in the year 2002. The new facility features pretreatment with potassium permanganate and powdered activated carbon, lime softening, granular activated carbon contactors and ultrafiltration membranes. It is currently the largest ultrafiltration membrane surface water supply in the United States.