Sometimes my toilet makes a horrible noise after it's already been flushed and the water has stopped filling (and I've washed my hands and left the bathroom.) It's not a sighing or wooshing; it sounds like it's the pipes in the wall making a loud screeching sound. It's rather disconcerting. If I flush the toilet, everything goes back to normal and everything in the tank looks normal. This can go months without happening, but when happening, can happen once every few days. Would it be sediment in the tank that is causing this?