One way to save water is to install low-flow aerators on kitchen and bathroom faucets. They can be installed in minutes by screwing them into the end of faucets. While most aerators limit water to three gallons per minute, low-flow models are available for around $5 that can reduce the flow to as little as one GPM. This can reduce faucet water usage and save energy.
After years of daily use, a faucet may develop a leak around the handle when it is turned on, or drip constantly from the faucet no matter how hard you try to turn it off. Both problems can often be solved by replacing the washer and sealing the valve threads with Teflon tape.