The problem with water consumption limits is..
That they don't take into account local factors. I live in a part of the UK where there is very rarely (every 20 years from experience) any shortage of water, yet I'm still forced to have showers with poor flow and toilets that barely shift the detritus from the bowl, nevermind down the 10m of soil pipe to the sewer. Water is in plentiful supply where I live, but because it can get a little short in and around the capital, we all have to suffer.