Reference Guide Correction
Outdoor water use reduction
LEED BD+C: New Construction, LEED BD+C: Core and Shell, LEED BD+C: Schools, LEED BD+C: Retail, LEED BD+C: Healthcare, LEED BD+C: Data Centers, LEED BD+C: Hospitality, LEED BD+C: Warehouses and Distribution Centers
Rating System Version:
v4 - LEED v4
Further Explanation- Examples, Example 1
- Building Design and Construction, v4 edition
Description of change
Revise the text below Figure 2 (that begins with "The landscape water allowance...") to read:
"The landscape water allowance (30% below baseline minimum) equals 43,980 gallons a month. The landscape water requirement for this design in this location is 15,939 gallons a month. The total savings without alternative water sources equals 75%. The project achieves the credit and earns 1 point.
The team has determined that rainwater harvested from the building’s roof will supply all the project’s outdoor water needs. Given the average monthly rainfall in this location and the roof’s area, the average monthly rainwater available for harvesting is 18,360 gallons per month:
Equation 1 in Step-by-step is used to calculate the amount of rainwater harvested from the roof:
Gallons per 1 inch of rain = 9,000 ft2 x 0.6
Gallons per 1 inch of rain = 5,400 gal
Equation 2 in Step-by-step is then used to determine the monthly harvested rainwater volume:
Amount available = 5,400 gal/in x 3.4 in/mo
Amount available = 18,360 gal/mo
The team ensures that the rainwater needed in the peak watering month can be stored on-site and installs a rainwater cistern capable of holding 20,000 gallons of rainwater for irrigation.
Equation 3 in Step-by-step is used to determine the adjusted landscape water requirement:
Adjusted LWR = 15,939 gal/mo - 18,360 gal/mo
Adjusted LWR = -2,421 gal/mo
The total water requirement is 15,939 gallons a month. Minus the 18,360 gallons a month available for harvesting, the project uses –2,421 gallons a month (i.e., it has a rainwater surplus). The total savings is 100%, for 2 points."
Related Addenda and LIs