Got a large water bill - my daily consumption was 500 litres/day more than previous bill. So started replacing tap washers ... found the culprit was the backyard garden tap. The end of the hose was out of sight below a pile of leaves in a pit. When I unscrewed the tap, I found the washer had 2 splits,
90 degrees apart, so water was just pissing through. BTW I bought that washer from a hardware chain known for sausage sizzles.