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Water Budget


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Water Budget Contents:

DEFINITION
CONSIDERATIONS
COMMERCIAL STATUS (not applicable)
IMPLEMENTATION ISSUES
GUIDELINES

RESOURCES


DEFINITION:

The indoor and outdoor water budgets are the calculated amount of water a household will require based on the size of the family, number and types of fixtures, and landscape needs. The landscape needs are based on turf water requirements only.


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
technology suppliers cost financing public regulatory
Indoor Water Budget
Outdoor Water Budget
Legend
green Satisfactory
yellow Satisfactory in most conditions
red Satisfactory in Limited Conditions
black Unsatisfactory or Difficult

IMPLEMENTATION ISSUES

FINANCING:

Not applicable

PUBLIC ACCEPTANCE:

Good, if clearly presented.

REGULATORY:

Not applicable


GUIDELINES

  • 1.0 Indoor Budget
  • Based on the average per capita interior water use rates developed and used by the U.S. Housing and Urban Development (HUD).

    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.


    Directions: The water-using items are listed in the left-hand column. The use rate per person per day is shown in the next column. The third column is filled in with the flow rate. For example, the rating of gallons of water used per flush and the rated flow rate on the showerhead would be entered in this column.

    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:

    Toilets1.6 gallons per flush
    Showers2.5 gallons per minute
    Washing MachineThe family will buy a model using 35 gal. per load
    Dishwasher8.5 gal. per load
    FaucetsThis amount is fixed at 8.5 gallons
    BathsAverage use

    Family size: 3


    ITEMUSE RATEFLOW RATE# OF PERSONSTOTAL
    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
    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.


  • 2.0 Outdoor Water Budget
  • The calculation method is for sunny turf (lawn) areas only. Shaded lawn areas will have reduced water requirements. Soil type can also affect water demand. If no lawn is present and there is a maintained landscape, use water requirements provided by the nursery or landscape designer. This method will give a general indication of water demand only.

    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.


    OUTDOOR WATER BUDGET EXAMPLE

    Grass Type Factor Chart

    St. Augustine1.0
    St. Augustine/Bermuda Mix0.9
    Zoysia0.9
    Bermuda0.8
    Buffalograss0.5

    Calculation Sequence (chart follows):

    Step 1:

    Step 2:

    Step 3:

    Step 4:

    Step 5:


    Use this chart and Legend to fill in the Outdoor Water Budget for your own home.

    Grass Type Factor Chart

    St. Augustine1.0
    St. Augustine/Bermuda Mix0.9
    Zoysia0.9
    Bermuda0.8
    Buffalograss0.5

    OUTDOOR WATER BUDGET EXAMPLE

    GRASS TYPE:                 BUFFALOGRASS	
    GRASS TYPE FACTOR (GTF):    0.5	
    SQUARE FEET OF TURF (SQFT): 5,000	
    NATURAL RAINFALL (NR):      32
    
    
    SQFT: square feet of turf..................5000 CF/YR: cubic feet per year.................20,833 GTF: Grass Type Factor.....................0.5 G/YR: gallons per year.....................77,915 CFNR/YR: cubic feet of natural rainfall....13,333 GNR: gallons of natural rainfall...........99,733 NR: natural rainfall (Austin = 32).........32 STEP 1 50 X 5,000 SQFT / 12 = 20,833 CF/YR STEP 2 20,833 CF/YR X 7.48 X 0.5 GTF = 77,915 G/YR STEP 3 32 NR X 5000 SQFT / 12 = 13,333 CFNR/YR STEP 4 13,333 CFNR/NR X 7.48 = 99,733 GNR STEP 5 77,915 G/YR (Step 2) - 99,733 GNR(Step 4) = -21,818 WATERING REQUIREMENT This means that for 5000 square feet of Buffalo grass, 32 inches of rain gives almost 22,000 gallons more than is needed.

    If calculated for the other grass types, 5,000 square feet of turf will require from almost 27,000 gallons for Bermuda to over 58,000 gallons for St. Augustine.

    Use this chart and Legend to fill in the Outdoor Water Budget for your own home.


    RESOURCES


    PROFESSIONAL ASSISTANCE



    COMPONENTS / MATERIALS / SYSTEMS



    GENERAL ASSISTANCE


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