Older faucets use between 3 and 7 gallons per minute. Low-flow faucet aerators use no more than 2.5 gallons of water per minute. The aerators can be screwed into your existing faucets. A leaky faucet may simply need a new washer. Small faucet leaks can waste 20 gallons of water a day.
Large leaks can waste hundreds of gallons.
Turn off the water while shaving, brushing teeth, etc. Don't let the water run when you brush your teeth, wash your face or hands, or shave. This can save 3 to 7 gallons per minute. Using a wastebasket instead of the toilet for tissues and other bits of trash will save gallons of water that are otherwise wasted. Your dishwasher uses the same amount of water whether it is full or just partially full of dishes, so be sure to fill it.