sorry i can't help with ur question Marian, but i was just wondering about this 'run-off' problem!
i live in Englnad and we have no restrictions on washing cars and stuf (except in summer ay high droughts or sumthing) so i do not know what u mean exactly. is this sumthing to do with the water and the soap that u wash ur cars with running into the rivers??! is this a pollution problem?