Slippery statistics

On You and Yours today on Radio 4, with a drought order (i.e. hosepipe and sprinkler ban) imminent in the south and the east of England, they quoted a car magazine expressing the view that using a hosepipe on cleaning one’s car can actually use less water than a bucket and sponge.  I was not overly surprised, given that it is held that a dishwasher can use less H₂O for cleaning the dirt from a pile of washing-up than manually with a bowl.  The programme makers set a challenge between one of the magazine’s contributors and a bod from the charity WaterWise.  Using a hosepipe with a trigger (other modulators also available), the auto enthusiast used his spray for a grand total of two minutes on the three stages of pre-rinse, wash and rinse, consuming 24 litres of water – the charity guy managed to use 22 litres but had only cleaned half the car with that by the time the magazine writer had finished, the implication being that more water (and time) would have eventually been expended.  This efficiency makes a mockery of government restrictions on hosepipes.  However, if people with garages used it to house the car (as my grandfather does) instead of annexing it as another houseroom, they would only need to clean their car once a year instead of every two weeks and that is the best way to conserve water.