Assessing storage requirements, water and energy savings, and costs associated with a residential rainwater harvesting system deployed across two counties in Southeast Florida.

This article analyzes the feasibility of a widely-deployed residential rainwater harvesting (RWH) system for reducing demands and supplementing existing, centralized water supply systems in a heavily populated region in Southeast Florida. The analysis employs a unique integration of models and approaches, which are portable and applicable in diverse contexts and include: a nonparametric bootstrapping model for synthetically generating multiple realizations of regional rainfall, water supply and demand, and storage size and reliability outcomes; and an approach for determining expected water and energy savings and costs associated with the RWH system. Findings suggest that a RWH system designed to meet the outdoor irrigation demands of detached homes in Florida's Broward and Palm Beach Counties could meet 54% of the total additional water demand created by the growing population in this region. This is significantly greater than the percentages of demand that could be met by several proposed centralized approaches to water supply using groundwater recharge by reclaimed water, comparable to the percentage of demand that could be met by desalinating brackish water from the Floridian Aquifer, but less than the percentage of demand that could be met by a proposed new reservoir and canal system for groundwater recharge. The findings also suggest that the expected cost of water provided by the decentralized RWH system, which includes substantial savings in energy requirements and costs, would be significantly less than the expected costs of water provided by all centralized water supply system alternatives considered, with the exception of the reservoir and canal system.