5th UF Water Institute Symposium Abstract

Submitter's Name Richard Marella
Session Name Groundwater Resource Evaluation
Author(s) Richard Marella,  U.S. Geological Survey (Presenting Author)
  Darbi Berry,  U.S. Geological Survey
  Stacie Greco, Alachua County Enviromental Protection Department
  Uncertainty associated with estimating domestic self-supplied and private landscape irrigation water use
  Domestic self-supplied use includes water withdrawals from individual private wells that provide drinking water to those not served by public supply. An estimated 2.251 million residents in Florida were included in this category for 2012, for an estimated total water withdrawal of 211 million gallons per day. This withdrawal was based on an estimated domestic per capita use of 81 to 103 gallons per day (gal/d) multiplied by the population not served by public supply. Per capita values are based on domestic use of public supply water. To improve the estimate of per capita use, a small pilot project was conducted in Alachua County between 2011 and 2015. Ten domestic household wells were metered, and per capita water use for a twelve month period between 2012 and 2013 ranged from 66 gal/d to 300 gal/d. Although this sample size is small and the participants were not randomly selected, it indicates that per capita use may be under-estimated, particularly where water is used for landscape irrigation in addition to household use. Another source of error in estimating domestic self-supplied water use is not accounting for private landscape irrigation wells. Generally these residential wells are used solely for landscape irrigation purposes (primarily lawn irrigation) and household drinking water is provided by a public water supplier. Preliminary results indicate that for the twenty year period between 1995 and 2014, Manatee County issued 3,700 drilling permits for small landscape wells while Sarasota County issued 13,000. These wells have a significant impact on the public supply per capita calculations, because these households no longer use public supply water for landscape irrigation. The result of the use of a secondary source of water for landscape irrigation is a lower public supply withdrawal and a corresponding lower apparent per capita use, while the actual water withdrawal is often not accounted for in the estimates made for domestic self-supplied.