Here are 5 steps you can take to reduce your water usage (also excerpted from Water):
1. Remember the rhyme: "If it's yellow let it mellow, if it's brown flush it down." You will save a lot of water!
2. If you have an old toilet, you can reduce the amount of water it uses by putting a "displacement device" in the tank. Use small plastic bottles filled with water or a displacement bag designed for toilet tanks. Displacement bags may be available free from your local water department or can be purchased from a hardware store.
3. Avoid flushing anything down the toilet that has not previously passed though your digestive system, apart from toilet paper - it's a waste of water and might block the sewer. Bag it and bin it.
4. Choose a slimline toilet rather than a full-size toilet; they use a lot less water per flush.
5. When you are buying a new toilet, look for a dual-flush toilet, or a low-flush toilet, which uses only 1.6 gallons per flush.