CI projects must include in their water-use calculations any fixtures used by occupants, even if the installation of the fixtures is not within the scope of the project. For example, an office project that is not updating the base building bathrooms still needs to include those bathroom fixtures that the occupants will be using in the LEED water-use calculation.

Reductions in potable water used in flush fixtures can also contribute to the achievement of WEc2: Innovative Wastewater Technologies.

The baseline for commercial lavatory faucets has been changed in LEED 2009 to 0.5 gpm, from 2.5 gpm in previous LEED rating systems.  There are a handful of aerators and commercial faucets that perform better than 0.5 gpm, but the use of this low baseline means that you will probably need to focus on getting water reductions elsewhere.

Janitors’ sinks, pot-fillers, and tub faucets can be left out, as they are used to fill containers with a fixed water volume regardless of the flow rate.

Like the prerequisite, this credit only includes core water uses—bathroom sinks, toilets, urinals, showers, kitchen faucets and prerinse sprays. 

Run preliminary water use calculations to establish the baseline water use and confirm goals for water-use reduction. This should include clearly identifying target flow and flush rates for fixtures. 

Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example in an elementary school, teacher restrooms and student toilets have different usage patterns that would affect the water use calculations if the fixtures were different.  For example: 

Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example, employee restrooms and customer toilets in a retail store have different usage patterns that would affect the water use calculations if the fixtures were different. For example: 

If the numbers of FTE occupants or transient visitors are not known by the Core and Shell project, you can use the default FTE numbers based on square footage shown here, from the LEED Reference Guide Appendix 1.

The FTE occupancy number you use must be consistent with the FTE occupancy numbers used in all your other LEED credit submittals, including: 

WEp1: Water Use Reduction
SSc3.2: Alternative Transportation—Bicycle Storage and Changing Rooms
SSc3.3: Alternative Transportation—Parking Availability