Water Conservation Estimating Calculator

8/10/2019 Water Conservation Estimating Calculator

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DCA Water Conservation Estimating Calculator

Overview: The DCA Water Conservation Estimating Calculator offers a simple way to estimate possible savings, both in water anddollars that can be realized by implementing specific water conservation strategies, i.e. promoting water conservation devices, landscape

efficiency, and leak repair. A local official or advocate can enter the desired level at which a conservation strategy would be implemented in

their community and get a general estimate of how much water will be saved and the cost of implementing that strategy. Realizing that there

are many individually specific factors that go into the financial model of a water system, this calculator does not attempt to integrate thesecalculated savings into the overall management structure of the system. Rather, using estimated water saving factors and averages from

several studies and the cost of simple water-saving devices this calculator is intended to give a general picture of what strategies might

provide the most savings and work best within the existing water system.

The numbers generated by this calculator are only one piece of the complicated water management puzzle, but they may provide the

impetus for looking more deeply into a specific water conservation strategy. The Water Conservation Estimating Calculator can be found on

the CD-ROM located in the Presentations/Videos on Water Management section of the toolkit or is available on DCAs web page,

www.dca.state.ga.us.

General Notes: The Water Conservation Estimating Calculator is an Excel spreadsheet divided into four worksheets (note the tabs atthe bottom). The user will be entering information and seeing the results in the Calculator worksheet. The Calculator Source Values

worksheet contains the values that are used to make the estimations. These values were taken from various studies and reports on water

conservation; the sources for this information are listed in the worksheet labeled Bibliography. These instructions can also be viewed

under the Instructions tab.

Red tabs indicate a note containing additional and/or interpretive information. Point the cursor arrow on the red tab in order to view this

information.

The worksheets in the calculator are protected. This means that it will not be possible to enter or change data anywhere outside of theareas described above. Each worksheet can be unprotected by going to Tools, Protection, and choosing Unprotect Worksheet.

Landscape Efficiency and Water Conservation Information: The values for Promotion of Water Efficient Landscaping (Xeriscaping) and

Water Conservation Education & Promotion (estimated range) are included in the calculator mainly as reminders to incorporate these

strategies into any water conservation program. The values calculated under these two headings may be affected by many variables, and

therefore, should be considered only rough estimates. Nonetheless, outdoor water use is where the most amount of water is typically used

and should be addressed in every water conservation program.

Additional Considerations: On page two (at bottom) of the Water Conservation Calculator you will find blank boxes that will requireinformation from the local water manager. This information may not be as simple as these headings require it to be. Nonetheless, the cost

of treating both drinking and wastewater and the cost of improving or expanding infrastructure is integral information when trying to

determine the level at which your community should be engaging in water conservation. These blank boxes are included mainly as place

markers so that these costs are considered and a payback period for investing in the above water conservation strategies may be calculated.

E t i D t U fi t i f th l l t ill th t bit d f lt l h b t d f it l ti


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DCA Water Conservation Estimating Calculator

*Enter values into light green cells

Community Population 50,000

Water Conservation Strategy:

% ofHouseholds

installing

devices

# ofDevicesPut into

Use

Estimate ofWater

Savings perHousehold(gallons per

year)

Estimate ofWater System

Savings (gallons

per year)

EstimatedProgram

Cost

EstimatedCost/Gal ofWater Use

Reduction

Tank Bank 30.0% 5,660 3,869 21,900,000 3,340$ $0.0001525

Fill Cycle Diverter 20.0% 3,774 4,353 16,425,000 1,849$ $0.0001126Tank Dam 20.0% 7,547 12,091 34,433,962 28,075$ $0.0008153Flapper 15.0% 2,830 14,509 15,495,283 5,349$ $0.0003452Toilet Replacement with ULFT 5.0% 943 16,443 5,853,774 65,802$ $0.0112409Faucet Aerator 50.0% 9,434 6,529 23,242,925 16,887$ $0.0007265Low Flow Showerhead 40.0% 7,547 12,091 34,433,962 13,208$ $0.0003836Leak Drip Gauge/Leak Repair 20.0% 3,774 3,468 13,084,906 377$ $0.0000288

Leak Detection Tablets/Repair 30.0% 5,660 3,468 19,627,358 1,245$ $0.0000634

# Subtotal 76,819 184,497,170 136,132$ $0.0138689

Promotion of Water Efficient Landscaping (Xeriscaping)10 4,703 88,736,321 VARIES

Water Conservation Education & Promotion (estimated range)8

1,256 23,690,566 to to VARIES

3,139 59,226,415

Total Estimated Annual Water Savings (in gallons) 82,776 296,924,057to to

84,657 332,459,906


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Additional Calculations That Should Be Made Depending On Data Availability

Cost of treating equivalent (to water saved) drinking water

Cost of treating equivalent (to water saved) waste water

Payback Period

Cost of Expanding DrinkingWater Treatment Capacity

Cost of Expanding WasteWater Treatment Capacity

Money saved by

implementing waterconservationstrategy/delaying plant


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Use Type Conservation

DeviceUnit Costs

6 Average Savings

from ConservationDevice

(gallons/flush or

gal/min)3

Water Savings

Per Day perperson resulting

from Installation

of [1] water

conserving device(gallons)

Conventional

Fixture WaterUse

(gallons/flush

or gal/min)1

Average

Rate of Use(how people

use water in

flushes or

minutes perday)

2

Average

HouseholdSize

Total Water

Used byConventional

Fixtures (gal/

person/day)

Household Water

Savings Per yearresulting from

Installation of [1]

water conserving

device (gallons)

Toilet Tank Bank $0.59 0.8 4 5 5.0 2.65 25.0 3,869

Fill Cycle Diverter $0.49 0.9 5 5 5.0 2.65 25.0 4,353Tank Dam $3.72 2.5 13 5 5.0 2.65 25.0 12,091

Flapper $1.89 3 15 5 5.0 2.65 25.0 14,509Toilet Replacement $69.75 3.4 17 5 5.0 2.65 25.0 16,443

Faucet Aerator $1.79 1.5 7 2.5 4.5 2.65 11.3 6,529Showerhead Low Flow $1.75 1.25 13 3.25 10.0 2.65 32.5 12,091

Other Strategies Average Savings

Per Capita Per

Day

Leak Repair4 Detection Tablets $0.10 9.5 9.5

Drip Gauge $0.22 9.5 9.5

Public Education8

Basic Water Conservation Information/Ed2% to 5% reduction in end use

Efficient

Landscaping5

Low water-use

plants 7.5% reduction in end use

The values used for calculations in this matrix are provided merely for illustrative purposes. While they are based on real figures taken from various studies and publications, they may vlocal conditions.


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Information Sources:

2Average of water use ranges given in "Urban Water Demand Management and Planning", Duane D. Baumann, John J. Boland, and W. Michael Hanemann, McGraw Hill, 1998, 254.

4AWWARFResidential End Uses of Water Study Summary , 1999. This is an average only-it may very considerably depending on many factors.

6Niagara Conservation Product Catalog 2001. These are unit prices. Large quantity purchases such as municipal retrofit programs, may result in reduced prices.

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EPA estimates that using water efficient landscapes can reduce a household's water use by 7.5 percent. This percent reduction is multiplied by the Average water use per capita timeattain the potential water savings that could result from efficient landscapes. There are many variables that could affect this result so this value should only be looked at as a rough estim

Nonetheless, outdoor water use is the number one water use by residents and should be considered a target in any water conservatio program.

9It is assumed that a water conservation device is used by mulitple users in a household, therefore an average household size of 2.65 is factored into the equation (# of devices

distributed*average savings per device*2.65) Average household size is taken from the U.S. Census Bureau, Census 2000

1These are averages of the range of water use rates of the given plumbing fixtures. E.g. toilets range from 1.6 gpf to 7 gpf. Some communities may have more new houses than old, and

therefore have less water being used by toilets. However, this average would vary considerably depending on the amount of new development in the community and should be adjusted)

Vickers, "Water Use Efficiency Standards for Plumbing Fixtures: Benefits of National Legislation, " American Water Works Association Journal. Vol. 82 (May 1990):53. The average for fand showerheads are based on the average of flow rates given by Duane D. Baumann, John J. Boland, and W. Michael Hanemann in "Urban Water Demand Management and Planning

3Niagara Conservation Product Catalog 2001, leak detection figure was taken from AWWARF Residential End Uses of Water Study, 1999. Fill cycle diverter average is taken from a stud

conductd by Marriott International, Inc.

7Cost does not reflect bulk quantity discounts. Customized "water-saving kits" that include several different fixtures can be assembled and specially priced for jurisdictions wishing to pro

these to their citizens.8Based on an average taken from the EPA Office of Wastewater Management (compiled from various undisclosed sources). This is provided just as a "place-marker" for public educatio

understood that the savings resulting from public education will vary considerably (even more than the range of 2%-5% that EPA has come up with) with local demographics and conditio

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EPA Office of Water, Water Conservation Plan Guidelines. Percentage reduction in end use. Actual water savings will depend on local conditions such as number of residents with yardarea of yards, local climate and soils.

Water Conservation Estimating Calculator

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