Rating System

LEED BD+C: New Construction, LEED O+M: Existing Buildings, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v3 - LEED 2008, v2 - Schools 2007, v2 - LEED 2.2

Inquiry

This question is regarding the applicability of a process water re-use and treatment system for WE credits 1.1-3.2. Our coastal project is proposing the use of a ground-coupled open-loop heat rejection system with a side-stream desalination plant. The system draws non-potable brackish water from the ground, rejects heat from cogeneration and HVAC systems into the water and returns the rejected process water to the ground. The water is not potable source water (e.g. sourced from potable watersheds such as lakes and rivers) and stringent environmental regulations are in place with regard to pumping rates / volume, and quality of the return water. Approximately 10% of the rejected process water flow is diverted for re-use in the building. The diverted water is treated using a reverse osmosis desalination system. The treated water will be used onsite for irrigation and conveyance. Benefits of this system include a reduced impact on the already taxed local potable water supply, reliability of water source, and environmental benefit due to on site treatment and re-use. We believe we should be able to take credit for the municipal water savings resulting from this system, provided that energy use from the system is included in energy calculations. Please provide guidance for credit applicability.