Where Does Your Home's Water Actually Go?

The average American family uses more than 300 gallons of water a day at home, and roughly 70 percent of it is used indoors, according to the EPA. Inside the house, the biggest single use is toilet flushing (about 24 percent), followed by showers (20), faucets (19), clothes washers (17) and leaks (12). Outdoors, watering the lawn and garden takes most of the remaining 30 percent nationally, and far more in dry climates. Here is the full breakdown, why it looks the way it does, and how to find out where your own home's water goes.

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Home water use at a glance

Household water use is easiest to reason about in a handful of numbers. Note that some describe a whole household and one describes a single person, so they are not directly comparable.

The spread between homes is wide. Occupancy, fixture age, climate and irrigation each move the total. In the arid West, landscape irrigation pushes per-person residential use among the highest in the country. Treat 300 gallons as a midpoint, not a target.

Where indoor water goes

The most detailed picture comes from metering studies that log flow at individual fixtures. The Water Research Foundation's Residential End Uses of Water study (Version 2, 2016) did this in single-family homes and found average indoor use of about 138 gallons per household per day. This is how it divided:

Two patterns stand out. Bathroom uses (toilets, showers, faucets and baths) add up to about two-thirds of indoor water. And leaks, at 12 percent, use more water than dishwashers, baths and miscellaneous uses combined.

Why toilets, showers and faucets lead

Every fixture's share comes from two things: how often it runs and how much water each run uses. The leaders win in different ways.

Toilets win on frequency

Everyone flushes several times a day, so even a modest per-flush volume adds up. Current US standards cap new toilets at 1.6 gallons per flush, and WaterSense-labeled models use 1.28 or less. Older toilets used 3.5 gallons per flush or more, well over twice as much as a WaterSense model. That is why toilet replacement is one of the highest-impact upgrades in an older house.

Showers win on volume per use

New showerheads are federally limited to 2.5 gallons per minute, and WaterSense-labeled models to 2.0. At 2.5, a 10-minute shower uses about 25 gallons; at 2.0, about 20. For four people showering once a day, that 5-gallon difference is roughly 7,300 gallons a year.

Faucets and appliances

Faucets are the quiet third: dozens of short uses a day, from brushing teeth to rinsing dishes to filling a pot. Federal standards limit bathroom faucets to 2.2 gallons per minute, and WaterSense models to 1.5. Clothes washers use a large volume per load, so load count and machine age matter most. Dishwashers barely register at about 1 percent, because a modern machine uses little water per cycle. That is why the dishwasher versus handwashing comparison often favors the machine.

Where the hot water goes

Hot water is a subset of the same picture. The 2016 study found that hot water made up about a third of indoor use, roughly 45 gallons per household per day. Showers accounted for about 39 percent of that hot water and faucets about 34 percent. Clothes washers took about 10 percent. Toilets used essentially none. So the fixtures that matter most for your water heater's energy use are not the same ones that matter most for your total gallons.

Leaks: the use nobody chose

The EPA says the average household's leaks waste more than 9,300 gallons a year, and that about 9 percent of homes have leaks losing 50 gallons or more per day. The usual culprits are worn toilet flappers, dripping faucets and leaking valves. The 12 percent leak share in the table above and the EPA's annual figure come from different studies and methods, so expect them to differ, but both point the same way. Leaks are common, and most are cheap to fix. The EPA estimates that fixing easy leaks can save about 10 percent on a water bill.

Two checks find most problems:

1. The meter test. Stop all water use, note the meter reading, wait two hours without using any water, and read it again. Any change means a leak somewhere.
2. The winter bill test. Winter is when outdoor watering is at its lowest. The EPA suggests that a family of four using more than 12,000 gallons a month in winter likely has a serious leak.

For toilets specifically, add a few drops of food coloring to the tank and wait about 10 minutes without flushing. If color shows up in the bowl, the flapper is not sealing. The water leak cost calculator puts a price on what a leak like that is costing you.

Outdoor use: the swing factor

Nationally, about 30 percent of household water is used outdoors, but that average hides enormous variation. A condo with no yard has almost none. A large home with a lawn in a dry climate may use more water outside than in. Outdoor water is also the least efficient, since it evaporates, blows off target or runs off the surface. The EPA estimates that as much as 50 percent of outdoor water is lost this way with inefficient irrigation, and that an automatic system that isn't maintained properly can waste up to 25,000 gallons a year.

You can estimate your own outdoor share from your bills. Compare a summer month with a winter month. The difference is a rough measure of what goes to the yard, since indoor use changes little through the year. The sprinkler water cost calculator can turn that into dollars.

Real-world reference points

Benchmarks make your own numbers easier to judge:

Work out your own household's numbers

Your water bill already has the data. Check which unit it uses. Many utilities bill in gallons, but others use CCF (hundred cubic feet), where 1 CCF is about 748 gallons. Then divide:

For example, take a household of 3 with a 30-day bill of 8 CCF. That is 8 × 748 = 5,984 gallons, or about 199 gallons per day, or about 66 gallons per person per day. That is below the national average of about 82. If the same bill showed 16 CCF, the per-person figure would double to about 133, and a leak or heavy irrigation would be the first things to check.

For a fixture-by-fixture estimate rather than a bill-level one, the household water usage calculator lets you enter your own showers, flushes and loads and returns daily, monthly and yearly totals.

Where cutting pays off first

Because use is concentrated, savings are too. In rough order of payoff per dollar:

1. Fix leaks. A flapper or washer costs a few dollars, and the water is wasted around the clock.
2. Replace old toilets. The largest indoor use, and the one where old and new models differ most. The toilet water usage calculator shows the difference for your household.
3. Upgrade showerheads and faucet aerators. Cheap, quick and easy to reverse. The low-flow fixture savings calculator estimates what you would save.
4. Tune irrigation. Fix misaligned heads, water in the cooler part of the day and match schedules to the season.

The bottom line

A typical home uses more than 300 gallons a day. Indoors, toilets, showers, faucets and laundry account for most of it, with leaks a surprisingly large 12 percent in the 2016 study. Outdoors, the yard can matter more than everything inside the house. The averages are useful for orientation, but the number that counts is yours. Check the meter, do the bill math, and start with whichever of leaks, toilets, showers or irrigation the numbers point to.