Repair leaky faucets promptly; a leaky faucet wastes gallons of water in a short period.
Insulate your electric hot-water storage tank and pipes, but be careful not to cover the thermostat.
Insulate your gas or oil hot-water storage tank and pipes, but be careful not to cover the water heater's top, bottom, thermostat, or burner compartment; when in doubt, get professional help.
Install non-aerating low-flow faucets and showerheads.
Buy a new water heater. While it may cost more initially than a standard water heater, the energy savings will continue during the lifetime of the appliance.
Although most water heaters last 10-15 years, it's best to start shopping for a new one if yours is more than 7 years old. Doing some research before your heater fails will enable you to select one that most appropriately meets your needs.
Lower the thermostat on your water heater; water heaters sometimes come from the factory with high temperature settings, but a setting of 115°F provides comfortable hot water for most uses.
Drain a quart of water from your water tank every 3 months to remove sediment that impedes heat transfer and lowers the efficiency of your heater. The type of water tank you have determines the steps to take, so follow the manufacturer's advice.
If you heat with electricity and live in a warm and sunny climate, consider installing a solar water heater. The solar units are environmentally friendly and can now be installed on your roof to blend with the architecture of your house.
Take more showers than baths. Bathing uses the most hot water in the average household. You use 15-25 gallons of hot water for a bath, but less than 10 gallons during a 5-minute shower.