Sounds like your flowering well ,and your town water is from the same sorce , you should check in to that,because the readings you are getting are simular, both very soft water,with that said I agree your ppm readings are off , because with such soft water your plumbing should not have any problems. Im from the NE and also have a flowering well that flows out of the ground on my property ppm 20-22 ph 6.8 , My drilled well 225 ft deep, has a ppm of 16 and a ph 5.9 , this is on a .5 scale ppm meter , So I know I am really in the same sorce,but one would think the ppm would be lower in a flowering well ,because it is artisian and the water is under pressure so has constant movement there for not picking up minerals being able to sit in the earth for too long ,well this is what I read about flowering wells anywey, but go figure, but on the other hand my well water has a mineral taste but the flowering well is taste less and is clear as glass , again go figure.