CONSIDERATIONS:
The goal of the water budget is to show the homeowner how much water is used in the house. The flow rates of the fixtures and the appliances provided by the builder (i.e. commodes, faucets, showerheads, dishwashers) and added by the homeowner (i.e. clotheswasher) can be put in a budget form that helps the homeowners understand their water use.
The primary exterior demand for water is for watering lawns. The water budget format tells the homeowner how much water their turf should require based on size and type of grass.
The water budget establishes a baseline of how much the homeowner should expect to use in the house and where the water goes. Additional conservation strategies can be designed from the water budget information.
The figures derived from the Water Budget calculations are estimates. Personal lifestyle will determine the actual water use.
Commercial Status |
Implementation Issues |
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Indoor Water Budget | |||||||
Outdoor Water Budget |
Legend | |
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Satisfactory |
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Satisfactory in most conditions |
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Satisfactory in Limited Conditions |
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Unsatisfactory or Difficult |
Actual use rates for water fixtures will vary.
Some items in the indoor budget could be added to the home after the homeowners move in. Use average water amounts for fixtures that are not in place. This helps the homeowner decide whether to add a fixture or appliance that is more conserving than the average because they can see how it can affect the total.
Multiply the second column times the third column then times the fourth column (this is the number of persons in the household). The subtotal for each item is entered in the fifth column.
The figures in the fifth column are added up to show the amount of water used each day. This total can be multiplied by 365 (days) to give the amount of water that would be consumed in one year.
Use this Worksheet to calculate your own home.
INDOOR WATER BUDGET EXAMPLE
Fixtures and appliances in this home have the following flow rates:
Toilets | 1.6 gallons per flush |
Showers | 2.5 gallons per minute |
Washing Machine | The family will buy a model using 35 gal. per load |
Dishwasher | 8.5 gal. per load |
Faucets | This amount is fixed at 8.5 gallons |
Baths | Average use |
Family size: 3
ITEM | USE RATE | FLOW RATE | # OF PERSONS | TOTAL |
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Toilet | 4.0 flushes per person per day |
1.6 | 3 | 19.2 |
Shower | 4.8 minutes per person per day |
2.5 | 3 | 36 |
Washing Machine | 0.30 loads per person per day |
40 gal per load (avg.) |
3 | 36 |
Dishwasher | 0.17 loads per person per day |
8.5 | 3 | 4.34 |
Faucets | N/A | 8.5 estimated |
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Baths | 0.14 baths per person per day |
50 gal. per bath (avg.) |
3 | 21 |
TOTAL | 125.04 |
Daily total (125.04) times 365 days equals 45,639.6 gallons per year.
Use this Worksheet to calculate your own home.
To minimize water needs for turf areas, do not remove grass clippings, keep grass at the recommended cutting height with frequent cuttings, and use a natural soil amendment such as "Dillo Dirt." Note that watering rates will vary during the year, with most watering occurring in the summer. (See the Xeriscape Section.)
The outdoor Water Budget can be calculated for 5 (five) grass types.
Grass Type Factor Chart |
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St. Augustine | 1.0 |
St. Augustine/Bermuda Mix | 0.9 |
Zoysia | 0.9 |
Bermuda | 0.8 |
Buffalograss | 0.5 |
Calculation Sequence (chart follows):
Step 1:
(50 x SQFT) / 12 = CF/YR
CF/YR x 7.48 x GTF = G/YR
(32 x SQFT) / 12 = CFNR/YR
CFNR/YR x 7.48 = GNR
G/YR - GNR = water requirement in gallons
Grass Type Factor Chart |
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St. Augustine | 1.0 |
St. Augustine/Bermuda Mix | 0.9 |
Zoysia | 0.9 |
Bermuda | 0.8 |
Buffalograss | 0.5 |
OUTDOOR WATER BUDGET EXAMPLE
GRASS TYPE: BUFFALOGRASS GRASS TYPE FACTOR (GTF): 0.5 SQUARE FEET OF TURF (SQFT): 5,000 NATURAL RAINFALL (NR): 32