Sand-like particles and grit occur in the home plumbing as a result of rust particles from galvanized steel pipe and sometimes from mineral scale sloughing off the pipe wall. A steel table knife or pocketknife blade will crush rust or mineral scale, while true sand will resist crushing.

Sometimes, this grit causes premature failure of faucets. It will also affect the operation of faucet aerators. If your washing machine is filling too slowly, you should replace the screen filters where the hot and cold water hoses enter the back of the machine.