BAN BATH TIME!
Have a no-bath week, and take showers instead. Baths require almost twice as much water. Not only will you reduce water consumption but the energy costs associated with heating the water too.
Other options try bathing once or twice a month as a luxury and shower every other time. Maybe bath once a week but use less water. Or, it's nearly summer, just jump in a pool once in a while, you'll be fine ;)
Source: 50 Ways to Help