I think
@classic33 will know the answer to this question. If someone is running a business using a powerful jet washer to clean driveways, how much water will he be using per hour?
There is a reason for asking this. On Monday evening I had my hosepipe on to water some plants in my garden. I think I was running the tap (only turned one through one quarter) gently for a maximum of thirty minutes. I felt guilty not using water from the butts, but they are nearly empty.
Yesterday the man cleaning a driveway (two doors up from here) had his high pressure (industrial as opposed to domestic) washer on for at least two hours, possibly three. At times he was using the jet of water to remove the weeds at the edge of the driveway. I am sure that after the weedy area had got soaked, it would be easy to dig them out, rather than use his lazy method.