The LEED for Homes Rating System (v4) includes the Water Efficiency (WE) Credit: Outdoor Water Use, which awards points based on the ratio of turf grass (high water use) to native or adapted plants (low water use) in the softscape to reduce irrigation needs.
According to the LEED Reference Guide for Homes Design and Construction (v4):
WE Credit: Outdoor Water Use (1--4 points)
Reduce outdoor water use by selecting native or adapted plants and limiting turf grass. Points are awarded based on the percentage of softscape area:
< 5% turf grass and > 75% native or adapted plants: 4 points.
The total softscape area is used to calculate the percentages of turf grass and native/adapted plants.
Source: LEED Reference Guide for Homes Design and Construction, v4, Water Efficiency Credit: Outdoor Water Use, p. 98--99.
The LEED v4.1 Residential BD+C rating system confirms:
WE Credit: Outdoor Water Use
Achieve 4 points by ensuring less than 5% of the softscape is turf grass and more than 75% is native or adapted plants, based on area calculations.
Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.
Calculation for 4 points:
Total softscape area: 57,500 ft.
For 4 points:
Turf grass: < 5% of 57,500 ft = < 0.05 57,500 = < 2,875 ft.
Native or adapted plants: > 75% of 57,500 ft = > 0.75 57,500 = > 43,125 ft.
Evaluate options:
A . 12,600 ft turf grass and 40,000 ft native or adapted:
Turf grass: 12,600 / 57,500 = 21.91% (> 5%).
Native: 40,000 / 57,500 = 69.57% (< 75%).
Does not meet 4-point criteria (only qualifies for 1 point: < 60% turf, > 25% native).
B . 11,500 ft turf grass and 40,000 ft native or adapted:
Turf grass: 11,500 / 57,500 = 20% (> 5%).
Native: 40,000 / 57,500 = 69.57% (< 75%).
Does not meet 4-point criteria (qualifies for 2 points: < 40% turf, > 50% native).
C . 2,500 ft turf grass and 44,000 ft native or adapted:
Turf grass: 2,500 / 57,500 = 4.35% (< 5%).
Native: 44,000 / 57,500 = 76.52% (> 75%).
Meets 4-point criteria.
D . 4,500 ft turf grass and 44,000 ft native or adapted:
Turf grass: 4,500 / 57,500 = 7.83% (> 5%).
Native: 44,000 / 57,500 = 76.52% (> 75%).
Does not meet 4-point criteria (qualifies for 3 points: < 20% turf, > 75% native).
Option C (2,500 ft turf grass and 44,000 ft native or adapted landscape) meets the
requirements for 4 points.
The LEED AP Homes Candidate Handbook emphasizes WE credits, including outdoor water use, and references the LEED Reference Guide for Homes Design and Construction as a key resource. The exam is based on LEED v4, ensuring the relevance of the table's criteria.
References:
LEED Reference Guide for Homes Design and Construction, v4, USGBC, Water Efficiency Credit: Outdoor Water Use, p. 98--99.
LEED v4.1 Residential BD+C, USGBC LEED Credit Library, accessed via LEED Online (https://www.usgbc.org/credits).
LEED AP Homes Candidate Handbook, GBCI, October 2024, p. 12 (references study resources and exam scope based on LEED v4).
USGBC LEED for Homes Rating System (v4), available via USGBC website (https://www.usgbc.org/resources/leed-homes-design-and-construction-v4).
LEED v4.1 for Homes, USGBC, accessed via LEED Online, confirming softscape ratios.
