my washing machine is filling cold clean water on its own ?

could be the cold/hot inlet solenoid rubber not seating, a bit of rubbish has come through the supply pipe at the instant the valve needed to close.or a split rubber washer.(replacement valve will be needed)
you need to isolate the valves one at a time to see which is not seating,cold will fill machine quicker than hot due to the greater water pressure.
check if machine is plumbed to the u bend back siphoning maybe occurring(ignore if stand pipe fitted)
Question !
Why aren't you using your isolation taps/valves H/C this what they are fitted for after the washing has FINISHED.

wirecutterman
March 2009