Did you know that your humble toilet uses more water than any other fixture in your house? Depending on how old your toilet is, it can use as much as 27 percent of the water in your home [source: WaterSense]. Upgrading from an older toilet to a newer one can drastically reduce your home water use, but even better is a dual flush toilet.
You don't need to upgrade any of your plumbing to install a dual flush toilet, but you may need a plumber to do the deed for you. Basically, a dual flush toilet has two flush options: one for liquid waste, and one for...er..."solid waste." You don't need as much water to flush away liquid, so why use the same amount every time you flush? Dual flush toilets also use a different mechanism to flush waste away which means they're even more efficient in handling solid waste than a conventional toilet [source: The Energy Conscious.
If you can't swing a whole new toilet right now, you can also find kits at the hardware store and online that can convert your current toilet to a dual flush. These are very simple, and chances are you can install them yourself.