LEED (Leadership in Energy and Environmental Design Certification) Water Efficiency 4 — Questions and Answers
Question 1: Which LEED prerequisite requires a minimum 20% reduction in indoor water use compared to the baseline?
- Water Metering
- Outdoor Water Use Reduction
- Indoor Water Use Reduction (Correct answer)
- Cooling Tower Water Management
Correct answer: Indoor Water Use Reduction
The Indoor Water Use Reduction prerequisite in LEED v4 BD+C requires at least a 20% reduction in fixture water use compared to the EPAct 1992/ASME A112.19 baseline.
Question 2: A commercial building installs dual-flush toilets (0.8/1.28 gpf). How should LEED calculations treat the flush volume for this fixture?
- Use only the full-flush volume (1.28 gpf)
- Use only the half-flush volume (0.8 gpf)
- Use a weighted average based on estimated flush frequency (Correct answer)
- Use the baseline of 1.6 gpf unchanged
Correct answer: Use a weighted average based on estimated flush frequency
LEED requires using a weighted average of half-flush and full-flush volumes based on anticipated usage ratios (typically 50/50 or 67/33) for dual-flush toilets.
Question 3: Which of the following is NOT a recognized non-potable water source under LEED Water Efficiency?
- Captured rainwater
- HVAC condensate
- Municipal reclaimed water
- Water from dehumidification (Correct answer)
Correct answer: Water from dehumidification
While captured rainwater, HVAC condensate, and municipal reclaimed water are all recognized non-potable sources, dehumidification water is not explicitly listed as a recognized alternative source in LEED v4.
Question 4: What is the primary environmental benefit of reducing outdoor irrigation in LEED projects located in arid US regions?
- Reducing stormwater runoff
- Conserving scarce local water resources and reducing aquifer depletion (Correct answer)
- Lowering building energy use
- Improving air quality
Correct answer: Conserving scarce local water resources and reducing aquifer depletion
In arid regions, outdoor irrigation reduction directly conserves scarce local groundwater and surface water resources, preventing aquifer depletion and reducing pressure on municipal water supplies.
Question 5: A hospital is pursuing LEED certification. Which fixture type has a HIGHER baseline flow rate under LEED calculations compared to a typical office building?
- Urinals
- Lavatory faucets in patient rooms (clinical) (Correct answer)
- Standard tank toilets
- Showerheads
Correct answer: Lavatory faucets in patient rooms (clinical)
Clinical/healthcare lavatory faucets used for hand washing near patient care areas may have higher baseline flow rates (2.2 gpm) compared to the 0.5 gpm used for private office lavatories.
Question 6: A LEED project installs a blackwater treatment system that recycles water for toilet flushing on-site. This strategy contributes primarily to which credit?
- Outdoor Water Use Reduction
- Water Metering
- Indoor Water Use Reduction (Correct answer)
- Cooling Tower Water Management
Correct answer: Indoor Water Use Reduction
Treating and reusing blackwater for toilet flushing displaces potable water demand for indoor fixtures, directly contributing to the Indoor Water Use Reduction credit.
Question 7: Under LEED v4, what minimum number of subsystems must be metered to pursue the Water Metering credit (1 point)?
- 1
- 2 (Correct answer)
- 3
- 4
Correct answer: 2
LEED v4's Water Metering credit (1 point) requires metering at least two additional water subsystems beyond the whole-building meter.
LEED (Leadership in Energy and Environmental Design Certification) Water Efficiency 4
Which LEED prerequisite requires a minimum 20% reduction in indoor water use compared to the baseline?