Overview

The Water Efficiency category of the U.S. Green Building Council (USGBC) rating system for new construction version 2.2 (LEED-NC 2.2) consists of three credit subcategories which together may earn a possible five points (credits) maximum, not including exemplary performance (EP) points. The notation format for the credits is, for example, WEc1.1 for Water Efficiency credit 1.1. Also, in this chapter, to facilitate easier cross-referencing between this text and the USGBC rating system, the second digit in a section heading, equation, table, or figure number represents the credit subcategory number for sections that deal directly with a USGBC LEED-NC 2.2 credit subcategory.

The Water Efficiency (WE) portion deals with issues that reduce the use of potable water at the site and the discharge of wastewater from the site. This will help limit the amounts of freshwater drawn from our water bodies and aquifers, and then treated for distribution and use, which strain our freshwater supplies and our water infrastructure. It will also serve to reduce the wastewater volumes discharged to these receiving bodies. Although several of the credits in Water Efficiency might include a capital cost investment, all provide a means to potentially reduce the associated utility costs over the life of the building.

The three subcategories are Water Efficient Landscaping (WE credits 1.1 and 1.2), Innovative Wastewater Technologies (WE credit 2), and Water Use Reduction (WE credits 3.1 and 3.2). Basically, the first credit subcategory limits the use of potable water for outdoor uses, the second limits the production...