Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.2

Inquiry

This CIR describes our methodology for developing baseline water use for PSU Broadway Housing, a residential project. Please advise if this methodology is acceptable. Our baseline water use estimates have been calibrated to data from a 1999 American Water Works Association (AWWA) study on residential end uses of water. The study lists per capita daily water usage rates for conventional and "more efficient" water fixtures. The conventional fixture values were used for all baseline fixtures, except toilets. For toilets, the water efficient fixture rate was chosen as it corresponds to 1.6 gallons/flush, the current code standard. The AWWA information can be accessed on the following website: http://www.awwa.org/Advocacy/pressroom/statswp5.cfm All fixtures used code or standard flow rates; the daily uses and/or durations were adjusted for calibration, such that the overall gallons/person/day for each fixture type matched the study values. Calibration of Baseline Water Use by Fixture Fixture Type -- AWWA LEED Baseline Kitchen sink -- 6.7 = 2560 gal/day/384 occ. Lavatories -- 4.4 = 1680 gal/day/384 occ. Faucets -- 11.1* Sum of above = 11.1** Toilet -- 9.6* 9.6 = 3686 gal/day/348 occ. Shower -- 12.6 12.5 = 4800 gal/day/384 occ. Clothes Washer -- 15.1 15.0 =5760 gal/day/384 occ. * Based on low-flow fixture rates (1.6 gal/flush) ** The AWWA study listed only the overall faucet usage; breakdown to usage by kitchen sink and lavatory was based on professional judgment.