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

Abstract

This paper addresses a knowledge gap that exists for city- or neighborhood-wide applications of on-site water-conserving technologies, such as rainwater and gray-water systems. We develop a framework for evaluating policies requiring on-site rainwater and gray-water systems in residential units. Our 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 socio-economic characteristics. Evaluation results identify a potential 5.4 to 37.2 percent 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 the cost-efficiency of on-site water-conserving technologies across neighborhoods. Our findings present 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.