An alternative to bottled water is this
ZeroWater ZD-013 8-Cup Pitcher: Amazon.com:...
Unlike other systems this one takes it down to zero and you get a tester to keep a check on the filters. I got it for less than this so you would want to shop around. It has helped with the tearing for my two.
People think it is odd that we filter the dog water and the people drink out of the tap. But we have our priorities! One nice thing I did find with the tester is our house water is very low. Our little town makes their own water and they are doing a good job