Civil Engineering Reference
In-Depth Information
100
High Forecast
Average
Low Forecast
95
90
85
80
75
70
65
60
55
50
2000
2005
2010
2015
2020
Year
Fig. 7-4.
Sample population forecast
Industrial
•
Agricultural
•
The meter use and water use variation for each land use classification are determined.
In addition, the amount of unaccounted-for water should be determined.
Unit Demands
Of course, where service connections are metered, a utility can easily
add them to determine its total demand. Metered water use data are generally available
only on a monthly basis, although some utilities are metering remotely and can mea-
sure individual customer demands on a real-time basis.
Actual demands in gallons (or liters) per day for each connection classification will
vary depending on climatic conditions and rate structures, but typical ranges of average
daily demand (ADD) are as follows:
Single-family residential: 200-350 gpd (760-1,300 L / d)
•
Multifamily residential: 150-250 gpd (570-950 L / d)
•
Commercial: 200-500 gpd (760-1,900 L / d) or more
•
Of course, large lot sizes and residential irrigation demands can result in much higher
average summer demands than those just listed. Some find it more convenient to
express water use on the basis of gallons per day per acre for each land use category.
