I built a home 7 yrs ago, and the water has a slight blue color to it that is noticable when we fill the bath tub. It also leaves blue, gritty stains where it drips in the shower or sink. It seems to corrode the pop up drain plugs in all sinks and tubs. I recently cut out a chunk of the copper pipe, and it is blue inside. All soldered connections have the same blue discoloration to them and a "greasy" feel about them Strangley, there are 17 homes that drtaw from the same well on the same water system, and they do not suffer from this problem. What could this be???