Here's a "smack your head it's so simple" idea for reducing your water use at home. It's as simple as this:

Turn down your water meter tap.

Yep, that's it.  Reducing your mains water pressure by turning it down at the meter will reduce the flow of water to all your taps and water outlets in the home.  Your family will be forced to use less water as the flow rate will be reduced.

Try it for a month or three and see what it does for your water usage and water utility bills.