But where do you live? City water or well water? When we lived out on our property out east, the well water was so bad that even with every water system we tried the water still ruined clothes. And white clothes would always get red and brownish stains (not grey) but that may depend on the minerals in your water.
We had that problem too. We moved into our brand new condo, and it stained a TON of our clothes. They replaced the washing machine, but we were S.O.L with all the clothes it wrecked.