They're a public government entity, this information is freely available (FOIA) IF YOU ASK. Just call the K'zoo Water Department, M-F between 8 a.m. and 4:30 p.m. at (269) 337-8149 or email them at cokpublicservices@kalamazoocity.org. However, where the brewery actually sources its water from may be different. Based on the limestone-derived geology of almost all of southern Michigan, the water it likely to be rather hard, with a lot of dissolved Ca+ and Mg++ and other particulates. I've never been there, but the brewery likely filters (reverse osmosis, distillation, etc.) depending on the beer style.