Water Use Inventory

Water Use Inventory
*You will need a copy of a recent water bill. The bill will give both the
amount of water used and the cost.
1. What month and year is the bill for?
Most bills show billing in HCF

(hundreds of cubic feet) or
units, both of which are
equivalent to 746 gallons.
Most bills are bi-monthly
2. Which agency supplies your water?

3. On your water bill, find the amount of water used for the month(s):
(include units)
4. Calculate your average cost of water per gallon and per 1000 gallons. Show calculations:
Average cost of water (gallons) =
Average cost of water (1000 gallons) =
Note: Water prices vary widely around the country, but usually fall in a range of 1-3 $/1000 gallons
5. Is your water rate tiered (different for different quantities used)? List the rate structure from your bill, whether tiered or not.
Estimated Water Use

These figures are estimates. There is a tremendous amount of variation. For example, if you have a waterefficient showerhead the water flow will be about half the estimate below. If you have a water-efficient toilet the water
used per flush will be as low as 1.5-2 gallons per flush. The amount of water used for tooth brushing, shaving, hand and
face washing, and dishwashing will vary significantly based on the time spent and the faucet setting. The amount of
water used yard will vary depending on the area in need of water.
Use
Conditions
Estimated gallons
Shower
per minute
4-10
Fill bathtub
per use
30-50
Toilet Flushing
per use (flush)
Tooth brushing
per minute (letting water run)
Washing hands and face
Shaving
Cooking
per meal
Washing Machine
depends on setting
20-50
Dish Washing
by hand (per minute)
Dish Washing
w/machine (depends on setting)
15-30
Water Lawn
per minute (depends on area)
10-20
Lawn Sprinklers
per minute (depends on area)
5-20
Washing Car
per minute
10
Wash down driveway w/hose
per minute
10
Fill swimming pool
per use
20,000-30,000
Personal Water Use Inventory

For shared activities like washing clothes, calculate your share of the water. For example, if there are 4 people in your
house and the washing machine is estimated to use 40 gallons per load, your share is 40/4 = 10 gallons.
Use the data in the first table to fill in the Estimated gallons per use or unit of time, but change the figures in that
column if you have more accurate data about your personal water use.
Use
Number of
uses or time
used per day
Estimated
gallons per
use or unit of
time
N/A
N/A
Estimated
gallons used
per day
Estimated
gallons used
per week
Estimated
cost per
week
Cost per
gallon
Estimated
cost per
year
Showe
r
Fill
bathtub
Toilet
Flushin
g
Tooth
brushi
ng
Washin
g hands
and
Shaving
Cooking
Washin
g
Machin
Dish
Washin
g
Wate
r
Law
Lawn
Sprinkle
rs
Wash
Car
Wash
down
drivew
Fill
swimmi
ng pool
Other:
TOTALS
gallons
gallons
N/A
Water conservation and calculations

Purpose and background: To become familiar with various municipal water measurements, analyze personal and
local water use trends, calculate associated costs for water consumption, and think about ways to conserve water
resources.
Procedure: Think back to earlier this morning when you were brushing your teeth. Did you let the water run while
you were brushing? Brushing ones teeth with the water running continuously uses about 3 gallons/min on average.
Most people spend about 1-3 minutes brushing their teeth each time they brush their teeth. In the table below, you
will estimate your own water use assuming you try to use as little water as possible (i.e. conserving water as opposed
to letting the water flow). We want an estimate in gallons per minutean easy way to do this is just think of how
much water you could save as a percentage, and multiply that by the 3gallons/minute flow rate, to get an estimate of
your average rate of water use while conserving. Record estimates (in gpm) for yourself and four of your classmates,
and find the average of the rate of water use while conserving. Also, estimate your total time spent brushing your
teeth, four other peoples estimates, as well as, the average time spent brushing based upon your data.
Estimated water use (gallons/min) while conserving water {table 1}
Your estimate
Person #2s estimate
Person #3s estimate
Person #4s estimate
Person #5s estimate
Average estimate
Person #5s estimate
Average estimate
Total estimated brushing time per day (in minutes) {table 2}

Your estimate
Person #2s estimate
Person #3s estimate
Person #4s estimate
Analysis questions/calculations:
1. Calculate the amount of water used per day (in gallons) for just YOUR estimate when conserving and when no
conservation measures are used.
2. Calculate the amount of water used per day (in gallons) for the AVERAGE estimate data that includes your data,
and 4 of your classmates data. Again, calculate the number of gallons used when conserving and not conserving
water.
3. Convert your answers for question # 2 into total mL used per
First Value - Second Value
day (1 gal=3785 mL)
|
| 100%
(First Value + Second
4. Calculate the % difference between conserving and nonValue)/2
conserving water uses from question #3.
5. If the combined populations of Del Mar, Carlsbad and Encinitas total close to 250,000, how much water (in
liters) would be used each day if these people allow the water to run continuously while brushing their teeth (use
the average brushing time estimate from the table for your calculation).
6. How much water would be saved (in liters) if the people in question #5 conserved water (use the average gpm
estimate from the first table to do this)?
7
7. Assume the state of California has a population of 3 x10 people. How much water (in liters) could be saved if
the average Californian conserved at the rate of the average conservation estimate from the first table?
8. If the current U.S. population is about 307 million people, how much water (in liters) could our nation save each
day by implementing water conservation using the average estimate from the first table?
9. The data for question #8 represents the amount of water that could be saved nationally in one day if people
simply conserved water. How much water (in liters) would be saved annually?
10. Assuming the average cost of water is about $0.05 per gallon for tap water, how much money would be saved
annually in the U.S. if everyone conserved water while brushing their teeth (to convert from liters to gallons,
multiply liters by 0.26417)?
11. The current cost for an Ipad 2 is about $500. Based upon the amount of money saved in question ten, how many
people could get free Ipad 2s if everyone conserved water while brushing their teeth for one year?
12. The current volume of Lake Powell in Arizona is project to be about 17 million acre-feet. If one acre foot ( one
13.
14.
15.
16.
17.
18.
acre one foot deep in water) is equivalent to 12,200 gallons, about how long would it take the people Del Mar,
Encinitas, and Carlsbad to drain Lake Powell if nobody conserved water while brushing their teeth?
Bottled water is extremely popular in the United States, but consider how that compares to the price of tap water
you might get from your local water authority. Using your calculated price per gallon from your water bill, how
does that compare to the price of bottled water? Calculate the price of bottled water in per gallon assuming you
purchase a 500mL bottle of water for $1.00 (remember 1 gallon = 3.785 L).
Based upon your and your families water consumption, in which areas of water use (laundry, showers, etc.) do
you think your family could easily conserve water? Why?
Individually, which activity do you do that consumes the most water? Why do you think this activity consumes
so much water?
Based upon the cost of tap water that you calculated from you bill, do you think tap water is priced appropriately
or not? Why?
Orange and San Diego Counties are prone to drought, which can strain limited supply. As a citizen, do you
think we should be focusing efforts on conservation or increasing supply?
Assume you are a presidential candidate, and a reporter asked for your top three ideas related to water
conservation. What would you tell the reporter? Explain your three best water conservation ideas in detail.

Water Use Inventory

Uploaded by

Copyright:

Available Formats

Water Use Inventory

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Water Use Inventory

Uploaded by

Copyright:

Available Formats

What information is provided about estimating personal water use?

What information is provided about estimating personal water use?

What calculations are done to analyze water use data?

What calculations are done to analyze water use data?

Water Use Inventory

1. What month and year is the bill for?

Most bills show billing in HCF

2. Which agency supplies your water?

Average cost of water (gallons) =

Average cost of water (1000 gallons) =

Estimated Water Use

per use (flush)

per minute (letting water run)

Washing hands and face

per minute (letting water run)

per minute (letting water run)

by hand (per minute)

w/machine (depends on setting)

per minute (depends on area)

per minute (depends on area)

Wash down driveway w/hose

Fill swimming pool

Personal Water Use Inventory

Water conservation and calculations

Person #2s estimate

Person #3s estimate

Person #4s estimate

Person #5s estimate

Person #5s estimate

Total estimated brushing time per day (in minutes) {table 2}

Person #2s estimate

Person #3s estimate

Person #4s estimate

You might also like