Low-flow showerhead can cut your water bill.

Heating water for showering, doing laundry, washing dishes, and other tasks is a household's second largest energy expense—after heating and cooling—according to the U.S. Energy Information Administration. Running your hot water heater can account for up to 20 percent of your utility bill.

Turning off the shower while you soap up is one way to cut your hot water bill. If that sounds unappealing, you'll be happy to know there are other ways to see real savings without sacrificing comfort, from changes of habit that cost nothing to simple DIY home improvements to large investments that pay off over time.

Let’s start with the small stuff.

No-Cost Changes of Habit

In the bathroom. There’s nothing like a luxurious bath . . . to run up your hot water bill. Especially if you fill the tub. Showers use a lot less water, even less if you have a low-flow showerhead. A water-saving showerhead rated for 2 gallons per minute uses 20 gallons during a 10-minute shower. Compare that with the 70 gallons needed to fill up some bathtubs. (A standard showerhead uses 2.5 gallons of water per minute.)

More on Energy Efficiency

In the laundry room. Unless you have a really dirty load, you don’t need hot water to get your clothes clean. Using warm water instead of hot can cut a load’s energy use in half, according to the Department of Energy, and using cool water will save even more. 

“Most laundry detergents work in cool water,” says Enrique de Paz, who oversees our laundry detergent tests. "Our tests have shown that." Even if you prefer to wash with hot or warm water, rinsing with cool water will get the job done for less money.

In the kitchen. The first rule of thumb is to not rinse your dishes before putting them in the dishwasher. When you do that, you’re using hot water twice—in the sink and in the dishwasher. Worse, prerinsing can cause the sensor in your dishwasher to misread how dirty your dishes are and adjust the settings to a lighter wash than they actually need. And only wash full loads of dishes. You should also avoid using the rinse-hold on your machine for just a few dirty dishes because it uses 3 to 7 gallons of hot water each time.

Another quick trick is to put the faucet lever on the kitchen sink in the cold position when using small amounts of water like rinsing your veggies. Putting it in the hot position draws hot water—firing up your hot water heater—even though it may never reach the faucet.

Low-Cost Home Improvements

Control your water temperature. Though the DOE says you can save money on hot water by lowering the maximum temperature of your water heater from 140° F to 120° F, we don’t necessarily recommend it. That’s because the lower temperature might invite opportunistic bacteria—including Legionella, associated with Legionnaires’ disease—to proliferate.

Another federal agency, the Occupational Safety and Health Administration, advocates setting domestic water heaters to a temperature of 140° F and using anti-scald devices such as thermostatic mixing valves at each faucet. Some shower fixtures also allow you to set a lower temperature.

Though you can wash clothes at a lower temperature, 140° F is recommended for washing dishes. “Fortunately, most dishwashers have a heating element that boosts the water temperature to 140 degrees,” says Larry Ciufo, who oversees CR’s dishwasher tests.

Fix leaks. If you have leaky faucets, showerheads, or pipes, you may be paying for hot water that’s literally going down the drain. The DOE says that a leak of one drip per second wastes 1,661 gallons of water a year and can cost up to $35 per year, depending on your water rates.

Fixing a leaky faucet may be as simple as replacing a washer or a showerhead, some of which are easier to fix than others. If you have a leak behind your walls, however, you’ll need to call a plumber. A musty smell, mildew, or moisture on a wall are all telltale signs of a leak.

Insulate your water heater. If you bought a new tanked water heater in the past three years, it is likely to be well-insulated, because new water heaters have to be more energy efficient to meet federal standards. If you have an older water heater and it’s warm to the touch, then you should consider insulating it. That can save you up to 16 percent in water-heating costs every year.

Before you get started, check your owner’s manual to see what type of insulation to use and how to wrap the tank (there are different methods for gas and electric). Also, check with your utility—some will install insulation and others offer rebates to homeowners who insulate their hot water tank.

Large Investments With Big Payoffs

Buy a new water heater. Typically, homeowners replace their old water heaters with one of the same type (tank or tankless) and fuel source (gas or electric). New storage tank water heaters are more energy efficient than models built before 2015, and tankless on-demand water heaters are even more energy efficient than that.

Consumer Reports recently tested gas and electric tankless water heaters and compared the annual operating costs with storage tank water heaters. The tank water heaters cost less to buy and install but more to operate than tankless water heaters. But replacing a tank water heater with a tankless model can be an expensive proposition. “You’ll have to upgrade your plumbing and maybe your electric service, too,” says John Banta, who oversees our water heater tests.

Buy an Energy Star washing machine. Consider upgrading your clothes washer. Energy Star says that you could fill three backyard swimming pools with the water you save over the life of a new Energy Star certified washer—a decade or so. New Energy Star washers use 25 percent less energy and 33 percent less water than standard washers. And because of their faster spin cycles, they wring more water out of your laundry, cutting dryer time—a bonus savings. Most of the washing machines in CR's tests are Energy Star certified.

Buy an Energy Star dishwasher. Dishwashers that earn the Energy Star use 31 percent less energy and 33 percent less water than standard dishwashers. And newer dishwashers have soil sensors that adjust the wash cycle for optimal cleaning. You’ll also appreciate how quiet new dishwashers can be, so they won’t disturb you while you’re adding up how much money you saved on your water bill. But before choosing a dishwasher, check how it rates for energy efficiency in our dishwasher tests.