TIP: Consider switching to a low-flow toilet.

According to the U.S. Government’s Environmental Protection Agency, about 41% of our indoor water use in the home goes toward flushing the toilet and 33% goes to bathing! Modern low-flush toilets are designed to use water efficiently. Here’s a website that has lots of information on reducing water use with a low-flush toilet and other simples changes in the home.
Want to get extra fancy? Well, the EPA has a new WaterSense label for toilets that use even less water than a standard low-flow toilet. These models are based on extensive studies of fluid dynamics over the last several years, so they work, and they work well.
If you don’t switch to a low-flush toilet, you can also use low-tech methods like putting a brick or a small milk jug in the tank to reduce water use.