Kentucky's bluegrass area (where my mother is) is entirely lime stone. Lime stone happens to dissolve trivially in water along with anything held in it. This wa

Kentucky's bluegrass area (where my mother is) is entirely lime stone. Lime stone happens to dissolve trivially in water along with anything held in it. This was literally what the doctor told her and isn't hard to believe[1]. From that article, """Median values of TDS were found below the SMCL of 500 mg/L, but outliers were common, especially in the Bluegrass (Figure 34).""" She has to get one of the Zero filters[2] which removes virtually all TDS[3] and measures it using a little TDS meter. Parts of the bluegrass are super high (> 500 TDS) and they happen to be in that part. I believe it is very low in most the united states for sure, but not where my family is from (I live in Chicago currently) :) [1] http://water.ky.gov/groundwater/Documents/BMU2_NPS_report3.pdf http://water.ky.gov/groundwater/Documents/BMU2_NPS_report3.p... [2] https://www.zerowater.com/ https://www.zerowater.com/ [3] https://en.wikipedia.org/wiki/Total_dissolved_solids https://en.wikipedia.org/wiki/Total_dissolved_solids