The indoor figures come from the national survey of home water use that EPA's WaterSense program relies on, per person and by use. Efficient fixtures cut the big three: toilets, showers and faucets.
How to use this calculator
- Enter the number of people.
- Choose the fixtures: a typical mix, or WaterSense models throughout.
- Enter the lawn area you water and how much you apply a week.
Worked examples
A couple
People in the home: 2 · Toilets, showerheads and faucets: Typical mix (as in EPA's survey) · Lawn you water: 0 sq ft
- Water use
- 117 US gallons a day
- A month
- 3,516 US gallons
- A year
- 42,778 US gallons
- Indoors, per person
- 58.6 US gallons a day
A family of four with a lawn
People in the home: 4 · Toilets, showerheads and faucets: Typical mix (as in EPA's survey) · Lawn you water: 2,000 sq ft · Water applied per week: 1
- Water use
- 412 US gallons a day
- A month
- 12,372 US gallons
- A year
- 150,526 US gallons
- Indoors, per person
- 58.6 US gallons a day
The same family, efficient fixtures
People in the home: 4 · Toilets, showerheads and faucets: WaterSense (efficient) throughout · Lawn you water: 2,000 sq ft · Water applied per week: 1
- Water use
- 378 US gallons a day
- A month
- 11,341 US gallons
- A year
- 137,982 US gallons
- Indoors, per person
- 50.0 US gallons a day
One person in an apartment
People in the home: 1 · Toilets, showerheads and faucets: WaterSense (efficient) throughout · Lawn you water: 0 sq ft
- Water use
- 50 US gallons a day
- A month
- 1,500 US gallons
- A year
- 18,253 US gallons
How much water a home uses
EPA puts the average American at about 82 gallons a day at home and an average family at about 300 gallons. Roughly 70 percent of household water is used indoors and 30 percent outdoors, and in the driest areas outdoor watering can reach 60 percent.
Indoors, the survey found about 58.6 gallons a person a day: toilets use the most, 14.2 gallons, then showers and faucets, 11.1 gallons each, the clothes washer 9.6 gallons, and leaks 7.9 gallons.
What efficient fixtures save
- Toilets: the federal limit is 1.6 gallons per flush; a WaterSense toilet uses 1.28 gallons per flush or less.
- Showerheads: 2.5 gallons per minute at most by law, 2 gallons per minute for WaterSense.
- Bathroom faucets: 2.2 gallons per minute by law, 1.5 gallons per minute for WaterSense.
- An ENERGY STAR clothes washer uses about 14 gallons a load, against 20 gallons for a standard one.
- Leaks waste about 9,400 gallons a year in an average home: a running toilet or a dripping faucet is worth fixing first.
Watering the lawn
Most lawns need about 1 inch of water a week, rain included, and every inch over a square foot is 0.623 gallons per square foot of water. A big lawn watered all summer can use more than the whole house indoors.
Common questions
How much water does a person use a day?
About 82 gallons at home, indoors and out, by EPA's figures; indoors alone, about 58.6 gallons.
How much water does a family use a month?
An average family uses about 300 gallons a day at home, which adds up to many thousands of gallons a month. The calculator works it out for your household.
What uses the most water in a house?
Toilets, then showers and faucets indoors; outdoors, lawn watering can top them all in summer.
How much water do leaks waste?
About 180 gallons a week, or 9,400 gallons a year, in an average home.