Latest Activity: ARCSA, in collaboration with partners UA, LiUNA, IAPMO and RMS, is developing a research paper on rainwater quality issues and areas lacking research. Additionally, ARCSA is compiling case studies on successful rainwater and stormwater catchment systems at federal and commercial buildings.

Activity Anticipated Through March 2026

Description: This action will focus on advancing nonresidential stormwater and rainwater catchment systems for potable and non-potable water reuse applications. Compared with residential systems, nonresidential systems involve a higher standard of water quality and monitoring. These more sophisticated systems can supplement a traditional water supply and be deployed to meet critical water needs during disaster scenarios. Action leaders plan to develop a white paper and provide information to assist in safely implementing nonresidential stormwater and rainwater catchment systems.

Background: Throughout history, rainwater and stormwater harvesting have been used to extend water supplies, particularly in regions where other water resources are scarce or difficult to access. In recent years, policymakers and industry stakeholders have shown renewed interest in alternative water sources due to rising water demand, interest in conserving both water and energy, and an increased regulatory emphasis on reducing stormwater runoff volumes and associated pollutant loads.

ARCSA has 30 years of experience designing stormwater and rainwater catchment systems, and it provides third-party certification training for designers, installers, and inspectors for these systems. ARCSA has recently proposed updating its current Standard 63 for catching and using rainwater to reflect the 2024 ARCSA Standard 63 white paper, which includes using log reduction targets for pathogens (WRAP Action 2.18 | EPA).

Currently, rainwater and stormwater initiatives and treatment requirements differ by state, which can cause confusion and hinder implementation of these systems. Herein, action leaders seek to educate state policymakers on the basics of rainwater and stormwater catchment systems and encourage industry to adopt a standard. A forthcoming white paper will provide case studies and information on the basic components of rainwater catchment systems designed per the industry standards and highlight opportunities to remove barriers to implementing non-residential rainwater and stormwater catchment systems.

Opportunities to be Gained:

• Improve acceptance and implementation of nonresidential rainwater and stormwater catchment systems.
• Educate the public on the main components of a rainwater / stormwater system designed to the ARCSA American Society of Plumbing Engineers (ASPE) and American National Standards Institute (ANSI) Standards 63 and 78.
• Clarify the importance of regularly maintaining rainwater and stormwater catchment systems.

Strategic Theme Area: Water Information Availability