How to Calculate Water Use?

By PSU EcoMerge Capstone - 11:42 PM


According to Portland Water Bureau, residential use in Portland is about 52 gallons per person per day. Let's calculate how much water you spend on a day, a week, or even a year compare to the average Portlander. 



Toilets
5 times daily
Showerheads
5 min daily
Faucets
8 min daily
Pre 1994
5.0 gallon per flush (gpf)
3.0 gpm (gallon per min)
3.0 gpm
1980-1994
3.5-4.5 gpf
2.5 gpm

After 1994
1.6 gpf
2.0 gpm
2.5 gpm
Low-flow


1.5 gpm



Clothes Washer
7 loads weekly
Dishwasher
5 times weekly
1980-1990
51 gallons per load (gpl)
14 gpl
1990-1995

11 gpl
1995-present
43 gpl
7-10 gpl  
Front-loading
27 gpl


Toilet

_____ household members X 5 flushes per person per day X _____ gallons per flush = __A__ gal/day

Shower

_____ household members X 5 minutes per person per day X _____ gallons per minute = __B__ gal/day

Faucets

_____ household members X 8 minutes per person per day X _____ gallons per minute = __C__ gal/day

Clothes Washer

_____ loads of laundry per week X _____ gallons per load (now divide by 7 to get daily use) = __D__ gal/day

Dishwasher

_____ loads of dishes per week X _____ gallons per load (now divide by 7 to get daily use) = __E__ gal/day

OR

Hand-Washed Dishes

_____ meals per day that require dishwashing X 2.5 gallons of water per meal = __E__ gal/day
Other Usage 
Other water consumption around the house that was not mentioned above; for instance, fish tank, water gardens, cooking, etc... 
Estimated miscellaneous water use = __F__ gal/day
Add the values (A to F) to get the total daily water use of the appliances in your home.
Toilets
Shower
Faucets
Clothes Washer
Dishwasher
Others
Total








Divide this value by the number of household members to get the total amount of water consumed by each person. Is this value greater or less than the 52 gallons per person state average?
_____ gal/day divided by _____ household members = _____ gallons per person per day
Portland Water Rates, Fiscal Year 2016-2017, 1.8 gallons cost a penny. 

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