Updated Rainwater Harvesting Standard: Conserving Water for the Long Run

Rainwater harvesting systems have been used to provide precious water resources to areas where water is scarce and to conserve water in parts of the world where the growing population has increased water demand beyond the local water resource levels.

The United States, with its abundant natural resources, has not escaped this dilemma. Over the past decade, rainwater harvesting systems have become more common across North America.

Standardization of Rainwater Harvesting Systems

Historically, the construction of rainwater harvesting systems was based on the judgment of those installing the systems. Only recently have local agencies started to adopt codes, standards and guidelines to govern the construction of these systems.

Furthermore, in the U.S., code officials responsible for inspecting these systems have voiced their need for more detailed design parameters to ensure the safe implementation of these systems.

For this reason, the International Code Council and the Canadian Standards Association (CSA) formed a Joint Technical Committee on Rainwater Collection Systems, under the jurisdiction of the CSA Strategic Steering Committee on Construction and Civil Infrastructure and the Code Council’s Codes and Standards Committee.

The Code Council and CSA published their first rainwater harvesting system standard, CSA B805-18/ICC 805-2018 — Rainwater Harvesting Systems, in 2018.

The intent of this standard is to: 

• Provide detailed parameters to ensure rainwater harvesting systems are designed and installed in a way that protects public health and safety. 
• Make it easier for local jurisdictions to accept and approve rainwater harvesting systems. 
• Provide a framework for designers and code officials to implement systems meeting the intent of existing codes. 
• Provide different methods for protecting water based on the influent water quality, the system, and the application. 
• Require that a water safety plan be developed for all rainwater harvesting systems.

This standard is referenced in Section 1301.1 of the 2021 International Plumbing Code® (IPC) and Section P2912.1 of the 2021 International Residential Code® (IRC).

Updated Edition of Rainwater Harvesting Systems Standard

The second edition of this standard, CSA B805:22/ICC 805:2022, Rainwater Harvesting Systems, was published in December 2022 and supersedes the previous edition.

It provides design, material, installation and operation parameters for residential and commercial systems that safely utilize rainwater for potable uses such as human consumption, food preparation and bathing, and rainwater and/or stormwater for non-potable uses such as irrigation, fire protection and toilet/urinal flushing.

Changes to this edition include updates to referenced standards, added definitions for different system types, changed filtration requirements for UV disinfection systems, and revisions to equations in Annex C.

SEE RELATED: Rainwater standard designed to help code officials 

This standard has been approved by the American National Standards Institute (ANSI) as an American National Standard.  This is the only ANSI standard that covers both rainwater and stormwater.  It has also been developed in compliance with Standards Council of Canada (SCC) requirements and has been published as a National Standard of Canada.

Adopting and Implementing Rainwater Harvesting Standards

CSA B805:22/ICC 805:2022 provides ways for property owners, builders, architects and engineers to construct new buildings, or renovate existing buildings, in ways that will protect our water resources today and tomorrow.

It is a voluntary standard that provides an alternate compliance path to existing codes. Therefore, no added construction cost is mandated to the user of the standard.

Rainwater collection is currently regulated by individual states. Because of this, the U.S. Department of Energy has compiled a state-level Rainwater Harvesting Regulations Map that can help stakeholders make strategic decisions on where to implement rainwater harvesting projects.

Join the Code Council’s Water Reuse Working Group

To advance water reuse opportunities, the Code Council has established a Water Reuse Working Group of code development leaders and industry experts to explore opportunities to better protect public health and to support state, local, tribal and territorial governments.

This group will research all aspects of onsite water reuse and recommend updates to the 2027 International Codes® (I-Codes) and standards necessary to meet water reuse goals.

To learn more about the Water Reuse Working Group and get involved, contact Rich Anderson at randerson@iccsafe.org or Kevin McOsker at kmcosker@iccsafe.org.

To learn more about the updated rainwater harvesting standard, click here.