Due to lousy water pressure (about 40 lbs.) and quality (lots of calcium), my cold water supply in my upstairs faucets and showers is little more than a trickle. I have removed and completely cleaned out the fixtures, but that does not help. They were not clogged to begin with. I did recently remove a valve in the basement that allows a trickle of water to a basement drain, it was full of build up. I suspect that the cold water supply line is slowly becoming clogged between the entry to the house and the upstairs fixtures. Is it possible to install a valve in the basement, shut off the main water supply, drain the lines, then chemically back flush the supply lines to clean them out? BTW – the hot water is ok, I drain the tank a couple of times a year which produces a lot of crap. Also, our city has recently installed new pumps which should raise the water pressure over the next several months. HELP! Thanks!