About 19 liters. (5 US Gallons)

The most I've been to don't allow it. I've just started to ignore it. Alternatively I can buy a Pressurewasher and they won't get my business anymore. I go to the Blauer Elefant in Kriens. It is not manned. I've been to other places with buckets where it was manned and haven't gotten comments as long as there is not a huge queue of cars.

I received the washing bucket with lid and Grit Guard.