What percentage of available roof area should a rainwater capture, storage, and reuse system be designed to use according to CALGreen standards?

According to CALGreen standards, a rainwater capture, storage, and reuse system should be designed to utilize up to 65 percent of the available roof area. This guideline is put in place to promote sustainable water management practices and enhance the efficiency of rainwater harvesting systems. By specifying a percentage, CALGreen encourages the design of systems that maximize the use of available resources while ensuring adequate storage and reuse capabilities to meet the needs of a given site.

Designing a rainwater capture system to this percentage helps to optimize collection without overwhelming the system, allowing for effective storage and usage throughout the year. It also balances the potential benefits of water conservation with practical considerations regarding structural capacity and system performance.