LEED-AP-HOMES practice question 17 of 35

Looking at the attached table, a project team is aiming for three points in Water Efficiency Credit, Outdoor Water Use. The site contains a total of…

Full set: 100 questions
Looking at the attached table, a project team is aiming for three points in Water Efficiency Credit, Outdoor Water Use. The site contains a total of 57,500 ft² (5,342 m²) of softscape. If the plan has 8,000 ft² (743 m²) of turf grass, what is the minimum area of native or adapted landscape required to achieve the desired three points for this credit? Turf grass area Native or adapted plant area Points 25% 1 50% 2 75% 3 75% 4
Answer options
A: 38,967 ft² (3,620 m²) of native or adapted plant area
B: 39,355 ft² (3,656 m²) of native or adapted plant area
C: 43,126 ft² (4,007 m²) of native or adapted plant area Correct answer
D: 2,784 ft² (259 m²) of native or adapted plant area
Correct Answer:
C. 43,126 ft² (4,007 m²) of native or adapted plant area
Explanation

To achieve three points for the WE Credit: Outdoor Water Use, the project must meet two requirements based on the provided table: the turf grass area must be less than 20% of the total softscape, and the native or adapted plant area must be greater than 75%.
1. Turf Grass Check: The turf grass area is 8,000 ft². As a percentage of the total 57,500 ft² softscape, this is (8,000 / 57,500) = 13.9%, which satisfies the < 20% requirement.
2. Native/Adapted Plant Calculation: The minimum required area for native or adapted plants is 75% of the total softscape: 57,500 ft² × 0.75 = 43,125 ft². The project must have an area greater than 43,125 ft². Option C, 43,126 ft², is the only value that meets this minimum threshold.

Why Incorrect

A. 38,967 ft² represents only 67.8% of the total softscape, which is insufficient to meet the > 75% requirement for three points.
B. 39,355 ft² represents only 68.4% of the total softscape, failing to meet the > 75% requirement for three points.
D. 2,784 ft² represents only 4.8% of the total softscape, which is far below the minimum threshold for earning any points in this credit.

References

1. U.S. Green Building Council. (2016). LEED v4 for Homes Design and Construction Updated July 2016. Washington, DC: U.S. Green Building Council. The requirements for this credit are detailed in the Water Efficiency (WE) section, under "Credit: Outdoor Water Use," Table 1, page 101. The table in the question directly reflects these point thresholds.

2. Krygiel, E., & Nies, B. (2016). Green Building: Principles and Practices in Residential Construction. John Wiley & Sons. (This is a textbook used in university curricula on sustainable design). Chapter 7, "Water Efficiency," discusses the principles of the LEED WE category, including the strategy of minimizing turf and using native/adapted plants to reduce outdoor water use, aligning with the credit requirements shown.

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