Residential irrigation water use in Central Florida

Automatic inground irrigation is a common option for residential homeowners desiring high-quality landscapes in Florida. However, rapid growth is straining water supplies in some areas of the state. The first objective of this study was to document residential irrigation water use in the Central Florida ridge region on typical residential landscapes (T1). The second objective was to determine if scheduling irrigation by setting controllers based on historical evapotranspiration (ET) (T2) and reducing the percentage of turf area combined with setting the controllers based on historical ET (T3) would lead to reductions in irrigation water use. The time frame of this study was 30 months beginning in January 2003. Irrigation accounted for 64% of the residential water use volume over all homes monitored during this project. The T1 homes had an average monthly water use of 149 mm/month. Compared to the T1 homes, T2 resulted in a 30% reduction (105 mm/month), and T3 had a 50% reduction (74 mm/month) in average monthly water use. Average monthly water use was significantly different (p < 0.001) across the three irrigation treatments. Setting the irrigation controllers to apply water according to seasonal demand resulted in significantly less irrigation water applied. In addition, increasing the proportion of landscape area from 23% (T1 and T2) ornamental plants irrigated with sprinklers to 62% and irrigated with micro-irrigation (T3) resulted in the largest reduction in irrigation water applied. Compared to T2 where only the irrigation controllers were adjusted, this additional decrease in irrigation water applied was a result of low volume application on only a portion of the landscaped beds where irrigation is only applied to the root zone of plants.