Some tips on saving water around the house

Some general information on household water conservation can be found here: 25 ways to save water, 100 ways to save water (bigger list, some stuff repeated). The two big ones are low-flow showerheads and faucet aerators. Even if you don't have a paltry $10 to spend on a low-flow showerhead (which, I might add, will easily save you that much per year on water), you can get low-flow faucet aerators at most home improvement stores for less than $5 each. They can reduce the water being used by your faucets by half.

In addition, even if you can't install a new low-flow toilet because you're renting, can't afford to right now, or whatever reason, you CAN put an inch or two of gravel or sand at the bottom of a two-liter plastic bottle, fill the bottle with water and stick that in your toilet's tank. You'll be saving a half gallon every time you flush.