A Regional Cost-Benefit Analysis of Rainwater Harvesting: Sustainable Economics to Justify Green Technologies

Rainwater harvesting (RWH) is an integrated water resource solution, capable of achieving multiple benefits in water conservation, stormwater management, combined sewer overflow (CSO) control, and energy efficiency. As is the challenge with many “green” solutions, the economics of RWH systems are not always financially feasible in the near-term. Depending upon the project location and climate conditions, potable water savings as a result of advanced RWH alone often cannot justify the upfront capital investment. A more holistic financial evaluation should be conducted across enterprise funds (water, wastewater, stormwater) to account for the full cost benefits/savings. The financial benefit that is frequently unaccounted for in RWH economic analyses is the cost benefit for reduced CSOs or other capital infrastructure or operations.This paper presents the RWH cost-benefit analyses performed for RWH systems in St. Louis, Missouri, and discusses regional opportunities for RWH systems. Additionally, financial incentives and credits (development and rate) for public-private partnering, allowing agencies to “affordably” implement green technologies such as RWH are discussed.