I agree,all tap water is different.I have a TDS reading of 135ppm coming from my tap.When i used to live 5 miles south of my current location,the water was horrible.It tested at 320ppm.As for distilled being better than RO/DI,i can't agree with that statement.You can't get any purepr than a 0ppm TDS reading which is what my RO/DI gives