LEED Water Efficiency Concepts 5 — Questions and Answers
Question 1: Under LEED BD+C, which of the following is an example of an 'alternative water source' that can reduce potable water demand?
- Municipally supplied reclaimed water used for toilet flushing (Correct answer)
- Water delivered by tanker truck for emergency use
- Potable water from an on-site well
- Hot water recirculated through the building's domestic hot water loop
Correct answer: Municipally supplied reclaimed water used for toilet flushing
Municipally supplied reclaimed (recycled) water is a recognized non-potable alternative water source for flushing fixtures.
Question 2: What does a 'water budget' approach in LEED landscape design involve?
- Calculating the maximum allowable irrigation volume based on plant species, climate, and area, then designing to stay within that limit (Correct answer)
- Setting a fixed dollar amount for annual landscaping water costs
- Restricting landscape area to no more than 20% of the project site
- Applying only drip irrigation to all planted areas to reduce surface runoff
Correct answer: Calculating the maximum allowable irrigation volume based on plant species, climate, and area, then designing to stay within that limit
A water budget sets an evapotranspiration-based limit on irrigation volume, guiding plant selection and system design to reduce outdoor water use.
Question 3: Which LEED credit rewards projects that achieve zero potable water use for irrigation?
- Outdoor Water Use Reduction at the maximum credit threshold (Correct answer)
- Rainwater Management at the highest tier
- Water Metering with advanced sub-metering
- Sustainable Sites: Reduced Site Disturbance
Correct answer: Outdoor Water Use Reduction at the maximum credit threshold
Achieving zero potable water for irrigation earns the maximum points available under the Outdoor Water Use Reduction credit.
Question 4: A hospital project team notes that sterilization equipment uses significant amounts of water. Under LEED, this is classified as what type of water use?
- Process water (non-regulated) (Correct answer)
- Regulated indoor water use
- Outdoor water use
- Emergency water reserve
Correct answer: Process water (non-regulated)
Sterilization equipment is a process water use, classified as non-regulated because it is not governed by standard plumbing fixture codes.
Question 5: What role does the 'Evapotranspiration Rate' (ETo) play in LEED outdoor water calculations?
- It represents the reference water loss from soil and plants, used to calculate baseline irrigation demand (Correct answer)
- It measures rooftop runoff rates during storm events
- It determines the efficiency rating of drip irrigation emitters
- It sets the minimum groundwater recharge required per site
Correct answer: It represents the reference water loss from soil and plants, used to calculate baseline irrigation demand
ETo is the reference evapotranspiration rate for a region, forming the basis of the irrigation water budget calculation in LEED.
Question 6: In a LEED project, condensate recovered from air handling units is best categorized as which type of water?
- On-site alternative water source suitable for non-potable uses (Correct answer)
- Potable water equivalent requiring no further treatment
- Blackwater requiring full sewage treatment before reuse
- Stormwater subject to local discharge permits
Correct answer: On-site alternative water source suitable for non-potable uses
HVAC condensate is a clean on-site alternative water source that can be collected and reused for toilet flushing, irrigation, or cooling tower makeup.
Question 7: Which LEED Water Efficiency strategy also benefits the Energy & Atmosphere category by reducing energy consumed for water heating?
- Reducing hot water fixture flow rates to lower domestic hot water demand (Correct answer)
- Installing rainwater cisterns to replace municipal supply
- Using reclaimed water for cooling tower makeup
- Metering irrigation systems to detect leaks early
Correct answer: Reducing hot water fixture flow rates to lower domestic hot water demand
Lower-flow hot water fixtures reduce the volume of water that must be heated, directly cutting domestic hot water energy consumption.
LEED Water Efficiency Concepts 5
Under LEED BD+C, which of the following is an example of an 'alternative water source' that can reduce potable water demand?