Just my 2 bits worth for you guys in Perth on water restrictions.
I work in an underground gold mine, and part of my job was to wash down old working areas where the gold was mined, with a 1 inch water hose, with a fair amount of pressure. Working a 10 hour shift, you do the maths and figure out how much water i used. Then times that by 7 for my other workmates. We've done this for years and are still doin it. Thats water straight from Mundaring.