A wash bay that drains into the street sends detergent, chain grease and brake dust into the sea about a hundred metres away. Every bay here drains through an interceptor that is cleaned out every fortnight, and the sludge goes for proper disposal.
The first rinse comes from two collected rainwater tanks on the roof, which saves mains water and, because it is soft, leaves fewer spots than mains water does. The final rinse is mains, because the tanks cannot be guaranteed clean enough for a finish coat.
We mention it because customers ask, and because the interceptor is the reason we could never work out of the back of a van the way the cheaper rounds do.