Learn to seek a leak. Many leaks are silent, with no visible signs in or around the house.
Repair dripping faucets by replacing washers. If your faucet is dripping at a rate of one drop per second, you can expect to waste 2,700 gallons per year.
Curious how much water a dripping faucet is wasting? Check out the AWWA's Drip Calculator.
Well water, check your pump periodically. Listen to hear if the pump kicks on and off while water is not being used. If it does, you have a leak.
Insulate your water pipes. You'll get hot water faster and avoid wasting water while it heats up.
Install aerators with flow restrictors to save water. To maintain pressure, clean filters occassionally.