TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesFor individual buildings, retail water consumption may be a significant end use. Itwas found that submetering arrangements for retail generally did not permitexclusion of retail water consumption from gross water consumption. This hasimplications for the ability of some buildings to be assessed against the NABERSbenchmarks.Leakage is, on average, the second largest end “use” of water in the samplebuildings. This is actually a conservative estimate as in some of the audits,leakage water use was allocated to the area of the building causing the leakage.This is both a major indictment and a major opportunity for water conservationpractice in this sector.The comparison of the median water consumption against that in the NABERSsample indicates some routine bias in the audit sample – indeed a t-test indicatesthat the difference in means is valid to a 99.5% confidence level, even once theNABERS sample has been adjusted to closely match the demographics (locationand size) of the audit sample. However, given that the audits were specificallyselected because of high water consumption, the presence of a routine bias is notsurprising. Indeed, given the high level of leaks reported, it would appearreasonable to assert that the majority of the difference can be allocated to leaks.The data sets align once the average leakage level is reduced to 33% of its originalfigure. This gives a notional average end-use breakdown that estimates averagepopulation end use as shown in Figure 4.Water Consumption (kl/m²)0.60.50.40.30.20.10CoolingtowersAmenitiesIrrigationRetailLeakageOther177