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Figure 5 - System-wide Gallons per Capita-Day
Per Capita-DayWater Use Per capita-day water use, expressed as gallons per capita-day (gpcd), also called gallons per capita per day, is a common way to normalize municipal water use data and can be a useful way to measure the success of water efficiency measures. The District calculates per capita-day water use in the following two ways:
System-Wide per capita per day water use = Total Billed Consumption ÷ Population ÷ Number of Days
Residential per capita per day water use = Billed Residential Consumption ÷ Population ÷ Number of Days
System-wide per capita-day water use includes all billed water consumption regardless of user type or water source. Using system-wide per capita-day water use to compare different communities can be misleading because the customer make-up of different communities can vary greatly. Figure 5 shows the system-wide per capita-day water use from 2000 through 2014.
Figure 5 - System-wide Gallons per Capita-Day
Residential per capita-day water use can provide a more “apples-to-apples” type of comparison, but it too can vary based on how a community calculates population. The District estimates population based on the number of residential and multi-family taps in Highlands Ranch and Northern Douglas County multiplied by household population and occupancy rates. Household population and occupancy rates are taken from the most recent Community Survey and U.S. Census data. Figure 6 shows annual residential per capita-day water use from 2005 through 2014.
