Water Usage Calculator

Water Usage is evaluated from Number of People, Average Shower Length and Showers per Day. The calculation reports Daily Water Use, Monthly Water Use and Estimated Monthly Water Cost.

Results

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About the Water Usage Calculator

Water Usage is treated here as a quantitative relation between Number of People, Average Shower Length, Showers per Day and Toilet Flushes per Person per Day and Daily Water Use, Monthly Water Use, Estimated Monthly Water Cost and vs. US Average.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
Shower: minutes x 2.1 gallons/min x showers per day
Laundry: loads/week x 20 gallons / 7
Dishwasher: runs/week x 6 gallons / 7
Other (faucets, drinking, cooking): 12 gallons/person/day

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

Shower: minutes x 2.1 gallons/min x showers per day
Laundry: loads/week x 20 gallons / 7
Dishwasher: runs/week x 6 gallons / 7
Other (faucets, drinking, cooking): 12 gallons/person/day

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Family of 4: 8-min showers, 5 flushes/day, 6 laundry loads/week, 7 dishwasher runs

Inputs

household_size: 4 shower_min: 8 showers_per_day: 4 toilet_flushes: 5 laundry_loads: 6 dishwasher_runs: 7
Daily Water Use: 164 gallons/day. Monthly Water Use: 4,918 gallons/mo. Estimated Monthly Water Cost: $19.67. vs. US Average: 164 gallons/day below US average (328 gpd for 4 people)

With Number of People = 4, Average Shower Length = 8, Showers per Day = 4 and Toilet Flushes per Person per Day = 5 as the stated inputs, the result is Daily Water Use = 164 gallons/day, Monthly Water Use = 4,918 gallons/mo and Estimated Monthly Water Cost = $19.67. Each value corresponds to the declared output fields.

Example 2: Water-conscious single person: 5-min shower, 4 flushes, 1 laundry load/week, 2 dishwasher runs

Inputs

household_size: 1 shower_min: 5 showers_per_day: 1 toilet_flushes: 4 laundry_loads: 1 dishwasher_runs: 2
Daily Water Use: 32 gallons/day. Monthly Water Use: 966 gallons/mo. Estimated Monthly Water Cost: $3.86. vs. US Average: 50 gallons/day below US average (82 gpd for 1 people)

With Number of People = 1, Average Shower Length = 5, Showers per Day = 1 and Toilet Flushes per Person per Day = 4 as the stated inputs, the result is Daily Water Use = 32 gallons/day, Monthly Water Use = 966 gallons/mo and Estimated Monthly Water Cost = $3.86. Each value corresponds to the declared output fields.

Example 3: High-use household: 15-min showers, 7 flushes/day, 10 laundry loads/week, 2 people

Inputs

household_size: 2 shower_min: 15 showers_per_day: 2 toilet_flushes: 7 laundry_loads: 10 dishwasher_runs: 3
Daily Water Use: 136 gallons/day. Monthly Water Use: 4,082 gallons/mo. Estimated Monthly Water Cost: $16.33. vs. US Average: 28 gallons/day below US average (164 gpd for 2 people)

With Number of People = 2, Average Shower Length = 15, Showers per Day = 2 and Toilet Flushes per Person per Day = 7 as the stated inputs, the result is Daily Water Use = 136 gallons/day, Monthly Water Use = 4,082 gallons/mo and Estimated Monthly Water Cost = $16.33. Each value corresponds to the declared output fields.

Example 4: US average reference: 2.5 people, typical usage

Inputs

household_size: 3 shower_min: 8 showers_per_day: 3 toilet_flushes: 5 laundry_loads: 5 dishwasher_runs: 5
Daily Water Use: 124 gallons/day. Monthly Water Use: 3,725 gallons/mo. Estimated Monthly Water Cost: $14.9. vs. US Average: 122 gallons/day below US average (246 gpd for 3 people)

With Number of People = 3, Average Shower Length = 8, Showers per Day = 3 and Toilet Flushes per Person per Day = 5 as the stated inputs, the result is Daily Water Use = 124 gallons/day, Monthly Water Use = 3,725 gallons/mo and Estimated Monthly Water Cost = $14.9. Each value corresponds to the declared output fields.

Common Use Cases

  • Calculate daily household water consumption
  • Identify highest water uses in the home
  • Estimate water bill based on usage