You are right and wrongIt's because the attitude to hygiene has changed in the UK. We are copying the Americans, who traditionally are more obsessive in this area. Back in the 1980s two showers/baths a week was seen as very respectable. I remember being lectured by my grandmother (who was born in 1917) back then about how you only need to have water up to your ankle in a bath to have a proper bath and any more was a waste. But nowadays, most people shower once a day. Also, washing your car back then was something you did only when it was obviously dirty, not something you feel obliged to do once a week!
the increase in showering and bathing is one of many factors, we over wash ourselves (many people having multiple showers per day) we over wash our clothes and other linen, we use to much crockery. We waste hundreds of litres of drinking water washing cars and watering ornamental gardens both of which are getting worse as cars have evolved into status symbols and global warming has turned our grass brown.The answer can never be solely stopping leaks, or building more reservoirs we need to educate people and reduce usage which almost certainly means compulsory water meters so people at least need some idea of how much they are using and a cost directly attached to that. We also need to mandate grey water systems in new builds and subsidise them in older houses the water boards could give every house a water butt for starters instead of paying a dividend this year!