This credit goes together with SS 2.5, which awards points for reducing irrigation demand by 25%. This “performance-based” approach requires a higher level of verification and site-specific, complicated calculations that only a trained landscape professional could do (which would likely cost extra). WE 2.3 and SS 2.5 both use the exact same calculation. You can get up to 6 points by reducing irrigation demand by up to 45% in SS 2.5, and an additional 4 points if you reduce it by 60% or more in WE 2.3. The only difference is that in the Sustainable Sites section, it focuses more on the types of landscape features, and in the Water Efficiency section, it focuses more on the design of the irrigation system itself. (I’m sure there were many discussions by the LEED Rating System authors on how to best spread out the points.)
Since we went for points in WE 2.1 and WE 2.2 (the prescriptive-based approach to water efficiency in irrigation), we cannot go for points in 2.3 (happily – I don’t know how to figure out the calculations). So, zero points here.
Water Efficiency points so far: 4
Cumulative points: 30
Additional points needed to get to Gold: 58