A rainwater harvesting system on site could be recognized in the Sustainable Sites Credit, Rainwater Management and the Water Efficiency Credit, Indoor Water Use Reduction. The Sustainable Sites Credit, Rainwater Management rewards projects that reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of the site1. A rainwater harvesting system can help achieve this by capturing and reusing rainwater on site2. The Water Efficiency Credit, Indoor Water Use Reduction rewards projects that reduce indoor water consumption by installing water-efficient fixtures and fittings3. A rainwater harvesting system can help achieve this by providing an alternative source of water for non-potable uses such as toilet flushing and irrigation4.

The other options are not correct. The Water Efficiency Credit, Water Metering does not recognize rainwater harvesting systems, but rather requires projects to install permanent water meters that measure the total potable water use for the building and grounds. The Water Efficiency Prerequisite, Outdoor Water Use Reduction does not recognize rainwater harvesting systems, but rather requires projects to reduce outdoor water consumption by using plant species that are native or adapted to the region and by using irrigation systems that are efficient and properly controlled. The Water Efficiency Prerequisite, Indoor Water Use Reduction does not recognize rainwater harvesting systems, but rather requires projects to reduce indoor water consumption by 20% from the baseline by installing water-efficient fixtures and fittings.

* Rainwater Management, p. 1

* NC-v4 SSc4: Rainwater management, p. 2

* Indoor water use reduction, p. 1

* NC-v4 WEc3: Indoor water use reduction, p. 3

* [Water metering], p. 1

* [Outdoor water use reduction], p. 1

* [Indoor water use reduction], p. 2