How US household water consumption is calculated
Domestic water consumption aggregates EPA WaterSense certified fixture standards: 2.0 GPM showerheads, 30-gallon bathtubs, 1.28 GPF toilets, 14-gallon washing machines and domestic sinks.
According to the US Geological Survey (USGS), average residential indoor water use in the United States ranges between 80 and 100 gallons per person per day.
Worked example
For a 3-person US household with 8-minute showers, 2 baths per week, 5 flushes per person/day, and 4 laundry loads per week:
Daily water use is 115 gallons (38 gallons per person per day, well below the USGS national average of 82 gal). Annual water volume is 42.0 thousand gallons, costing an estimated $462.00 per year.
Inputs for the US water calculator
Number of people in household
Total number of permanent occupants in the residence.
Daily shower time per person
Average minutes spent showering daily (standard US flow rate is 2.0 GPM).
Baths taken per week (whole home)
Total number of baths taken by all occupants each week (~30 gallons per tub).
Toilet flushes per person/day
Average daily toilet flushes per occupant (~1.28 gallons per flush).
Washing machine loads per week
Number of laundry loads run per week (~14 gallons per load for high-efficiency washers).
CALCULATOR QUESTIONS
Water calculator US questions
What is the average daily water usage per person in the US?
The US Geological Survey (USGS) estimates that each American uses an average of 80 to 100 gallons of water per day for indoor domestic purposes.
What is an EPA WaterSense label?
WaterSense is a voluntary partnership program sponsored by the US EPA that certifies fixtures that are at least 20 percent more water-efficient than standard models.