The median monthly bill is based on 10 hundred cubic feet (Ccf) or approximately 7,480 gallons. As expected, purchasing water results in the highest monthly customer bill. The hybrid approach appears to be the most economical for the customer, while the majority of utilities predominantly use surface water. To classify utilities, it was assumed the utility must obtain over 75 percent of its water from the particular source to fall in the respective category. If there is no predominant source, the utility is classified as hybrid.
The results of the trending analysis for the impact of water source on the median customer bill show significant increases in bills from 2008 to 2010 for utilities that draw surface and groundwater from 2008 to 2010 and from 2010 to 2012 for those that rely on purchased water. Utilities that have a hybrid water source result in a lower increase of the median customer bill over the four-year analysis.