The LEED for Homes Indoor Water Baseline Consumption is calculated using a standardized formula that estimates daily water use. This calculation requires three key inputs:

1. Fixture flow rates: The baseline assumes standard flow rates as defined by the Energy Policy Act of 1992 (e.g., 2.5 gallons per minute for showerheads).

2. Number of occupants: In LEED for Homes, the number of occupants is estimated based on the number of bedrooms (Occupants = Number of Bedrooms + 1). This determines the frequency of use.

3. Number of fixtures: The number of bathrooms is used to determine the quantity of water-using fixtures (showers, toilets, faucets) in the home.

B: The size of plumbing piping is a hydraulic design parameter and is not used in the LEED water consumption calculation.

C: The physical size of shower compartments is irrelevant to water use, and this option omits the critical factor of occupant number (bedrooms).

D: Recirculating shower systems are an advanced water-saving strategy considered in the design case, not in the baseline calculation, which assumes standard fixtures.

1. U.S. Green Building Council. (2015). LEED v4 for Homes and Midrise Reference Guide.

Page 169, WE Prerequisite: Indoor Water Use, Step-by-Step Guidance: The guide specifies the calculation methodology. It states, "The number of occupants is assumed to be the number of bedrooms plus one." It also provides a table with baseline (default) fixture flow rates and usage assumptions (e.g., showers: 1 use/person/day). This confirms the necessity of bedroom count and fixture flow rates. The number of bathrooms is required to tally the total number of fixtures for the home's overall baseline.

2. Krygiel, E., & Nies, B. (2016). Green Building: Principles and Practices in Residential Construction.

Chapter 6, Water Efficiency, "Calculating Water Savings": This academic text, often used in university curricula, explains that residential water use baselines for green building certifications like LEED are established using EPAct 1992 flow rates and occupant estimates derived from the number of bedrooms. It details how the number of fixtures (determined by counting them, often by bathroom) is multiplied by usage patterns tied to occupants.