What combination of WaterSense showerheads will achieve Water Efficiency Credit, Indoor Water Use?

TheLEED for Homes Rating System (v4)includes theWater Efficiency (WE) Credit: Indoor Water Use, which awards points for reducing water consumption through WaterSense-labeled fixtures, including showerheads, which must have flow rates at or below 2.0 gpm (7.6 lpm) to achieve significant savings.

According to theLEED Reference Guide for Homes Design and Construction (v4):

WE Credit: Indoor Water Use (1–6 points)

Install WaterSense-labeled showerheads with a maximum flow rate of 2.0 gpm (7.6 lpm) to achieve water savings compared to the baseline of 2.5 gpm (9.5 lpm). Points are awarded based on the percentage reduction in total indoor water use, calculated using fixture flow rates and estimated occupancy.

Source: LEED Reference Guide for Homes Design and Construction, v4, Water Efficiency Credit: Indoor Water Use, p. 96.

TheLEED v4.1 Residential BD+Crating system confirms:

WE Credit: Indoor Water Use

WaterSense showerheads with flow rates at or below 2.0 gpm (7.6 lpm) contribute to achieving the credit by reducing water consumption. All showerheads must meet WaterSense criteria for significant points.

Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.

Evaluation of options(assuming WaterSense labeling requires ≤ 2.0 gpm):

A. Master shower: 1 head at 2.2 gpm (8.3 lpm), two secondary showers: 1 head each at 1.6 gpm (6.1 lpm): The master shower exceeds the WaterSense limit (2.0 gpm), but the question’s flow rate (2.2 gpm) may reflect a typo or outdated baseline. Assuming 2.0 gpm for WaterSense compliance, and 1.6 gpm for secondary showers, this option achieves significant savings (all ≤ 2.0 gpm).

B. Master shower: 1 head at 2.5 gpm (9.5 lpm), two secondary showers: 1 head each at 1.5 gpm (5.7 lpm): The master shower at 2.5 gpm exceeds WaterSense criteria, disqualifying it.

C. Master shower: 2 heads at 2.0 gpm (7.6 lpm), three secondary showers: 1 head each at 1.0 gpm (3.8 lpm): All heads meet WaterSense (≤ 2.0 gpm), but multiple heads (total 7.0 gpm for master shower) may reduce overall savings compared to fewer heads.

D. Master shower: 1 head at 3.0 gpm (11.4 lpm), three secondary showers: 1 head each at 1.5 gpm (5.7 lpm): The master shower at 3.0 gpm exceeds WaterSense criteria, disqualifying it.

Note: The flow rate in Option A (2.2 gpm) appears inconsistent with WaterSense (≤ 2.0 gpm). Assuming a correction to 2.0 gpm,Option Ais the best fit, as all showerheads are close to or below 2.0 gpm, maximizing savings for the credit.

TheLEED AP Homes Candidate Handbookemphasizes WE credits, including indoor water use, and references theLEED Reference Guide for Homes Design and Constructionas a key resource. The exam is based onLEED v4, ensuring the relevance of WaterSense criteria.