What do your showers cost each year?

Where the money goes

A shower is two purchases at once: gallons of water and sewer service from your utility, and the energy that heats most of those gallons. EPA says showering accounts for nearly 17 percent of indoor water use in the average US home, and nearly 40 gallons a day for a family. Because water heating usually costs more per gallon than the water itself, a head that uses less water saves on both bills. The calculator adds them up for your own flow, time and rates, and compares with a second head, so you can see what a different showerhead is worth before you buy one.

The method

Gallons = flow (gpm) × minutes × showers a day × 365. Water cost = gallons ÷ 1,000 × price per 1,000 gallons (or gallons ÷ 748.1 × price per ccf). Heat = gallons × 8.3 Btu per gallon per °F × (shower temperature − cold water temperature). The 8.3 is the product of water's density and specific heat, as used in the DOE water-heater test. The fuel used is the heat divided by the heater's UEF (uniform energy factor), then divided by 3,412 Btu per kWh, 100,000 Btu per therm of natural gas or 91,452 Btu per gallon of propane. Multiply by the price of the fuel. The comparison runs the same calculation with the second flow.

Worked example

Two 8-minute showers a day with a 2.5 gpm head use 20 gallons each, 14,600 gallons a year, which is close to EPA's "nearly 40 gallons a day" for a family. At $10 per 1,000 gallons that is $146.00. Heating that water from 55°F to 105°F takes 6.06 million Btu; with an electric heater of UEF 0.93 that is 1,909 kWh, or $329.00 at 17.23¢. Total $475.00 a year, $0.65 per shower. A 2.0 gpm head saves 2,920 gallons (20%), 382 kWh and $95.00 a year. On a gas heater (UEF 0.62, $1.50 a therm, both placeholders) the same change saves $58.52. As a cross-check on the method: EPA's 2,700 gallons and 330 kWh imply a temperature rise of about 50°F at 100 percent efficiency, which is typical of a warm shower and city water, and our formula reproduces the 330 kWh from that rise (328 kWh). This is our own consistency check, not an EPA statement of its assumptions.

Limits of this method

• The temperatures and minutes are yours. We use no national average for minutes per shower or for inlet water temperature, because the sources we could verify (EPA's showerhead pages) do not give them. Measure with a thermometer and a timer.
• Hot water losses. Water that cools in the pipe while you wait for hot water, and standby losses in a tank, add to the bill and are not counted. DOE suggests insulating hot-water pipes (saves an additional 3%-4% per year on water heating) and, if you wait for the water to get hot, a showerhead with a temperature-sensitive pause switch.
• Lower flow only saves if the shower stays satisfying. If you stay in longer to get the same rinse, part of the saving disappears.
• UEF is a test result. The real efficiency of a heater in your house depends on location, tank temperature and use. Heat pump water heaters have UEF above 1, so the field accepts values up to 6.
• The label is not your flow. The 2.5 gpm figure is EPA's description of standard showerheads and 2.0 gpm is the WaterSense limit. Water pressure and wear can make the head you own deliver something different; do the bucket test.

How much water does a shower use?

Flow times time. A standard showerhead uses 2.5 gallons per minute (gpm), so an 8-minute shower uses 20 gallons; a WaterSense labeled head, limited to 2 gpm, uses 16. EPA says showering takes almost 17 percent of the indoor water in US homes, nearly 40 gallons a day for the average family, and about 1.2 trillion gallons a year nationwide. Your own flow can be measured by timing how long the shower takes to fill a 1-gallon bucket: 60 seconds divided by that time is your gpm.

How much does it cost to run a shower?

Two bills: the water and sewer bill and the water heating. With the placeholder numbers in the form (two 8-minute showers a day at 2.5 gpm, $10 per 1,000 gallons, an electric water heater at 17.23¢ per kWh, water heated 50°F) one shower costs about $0.65, of which the water is $0.20 and the heating $0.45. Per year that is $475.00. In this example the heating is the bigger half.

How much does a WaterSense showerhead save?

EPA says the average family could save 2,700 gallons of water a year and more than 330 kilowatt-hours of electricity by installing WaterSense labeled showerheads, and that national savings would be more than 260 billion gallons and $2.9 billion in water bills; EPA also says the average family could reduce its water and electricity costs by $70 a year. With the form's example (a 20 percent flow cut, from 2.5 to 2 gpm) the calculator gets 2,920 gallons, 382 kWh and $95.00 a year, the same order of magnitude. Your figure depends on how long and how often you shower.

What is the difference between 2.5 gpm and 2.0 gpm?

2.5 gpm is the standard maximum flow for showerheads (EPA calls standard showerheads 2.5 gpm); a WaterSense labeled showerhead must demonstrate that it uses no more than 2 gpm. That is 20 percent less water and 20 percent less water-heating energy, because the heater only warms what flows. The longer and more often you shower, the more the head change saves.

Why does the calculator ask for two temperatures?

The energy to heat water is gallons × 8.3 Btu per gallon per degree × temperature rise. The rise is the shower temperature minus the temperature of water entering the heater (it changes with the region and the season, so measure it with a thermometer at a cold tap). Showers run cooler than the tank, which DOE advises setting at 120°F, because the valve mixes cold water in; the mixing means that the energy depends on the shower temperature, not the tank. Tank and pipe losses are not included.

Water is priced per ccf. How do I convert?

One ccf is 100 cubic feet, which is 748.1 US gallons. Choose "per ccf" in the form and the calculator converts for you. At $4.5 per ccf (a placeholder), the example above costs $87.83 a year for water, against $146.00 at $10 per 1,000 gallons. Add the sewer charge into the price, since most utilities bill sewer by the water you use.

Sources: U.S. EPA WaterSense, Showerheads and Statistics and Facts (epa.gov/watersense, read October 28, 2026); U.S. Department of Energy, Energy Saver Guide 2022 (Water Heating); U.S. EIA, Electric Power Annual 2025, Table 2.4 (electricity price); energy content constants from the DOE water-heater test (10 CFR 430, Appendix E) and EIA. Related tools: water heater cost calculator, water heater size calculator, GPM calculator, electricity cost calculator. How we check our calculators.