depends on how much rain we get (on a well).. I've seen upper 400's to mid 600's on my tap.. excellent tasting water though if you don't mind mineral deposits.. also, less discolored than local city water with much lower tds (around 150-200 when I've tested before), local city water has a funny color hue to it when compared to my well water (point being, I feel safer drinking my high tds high mineral water than the processed, chemical filled stuff the local city pumps to people's houses).