Evaluation of Implementation Strategies of Onsite Water-Conserving Technologies in Three Urban Neighborhoods

Abstract

This paper addresses a knowledge gap that exists for citywide or neighborhood-wide applications of onsite water-conserving technologies, such as rainwater and graywater systems. A framework is developed for evaluating policies requiring onsite rainwater and graywater systems in residential units. This framework incorporates housing stock dynamics, fixture retrofitting, and water demand models. It assesses costs and benefits of policy implementation strategies for three urban neighborhoods selected according to their built environment and socioeconomic characteristics. Evaluation results identify a potential 5.4%–37.2% reduction in future neighborhoods’ water demand. With the most cost-efficient water-conserving technologies, a household is expected to save $160–$393 from their annual water bills. The cost-benefit analyses indicate substantial variation in water-saving potential and cost-efficiency of onsite water-conserving technologies across neighborhoods. The findings indicate that to maximize effectiveness, the specific choice of water-conserving technology and implementation strategy needs to account for local conditions of land-use characteristics, household structure, and water-fixture conditions.