TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesWATER CONSUMPTION IN OFFICE BUILDINGS INAUSTRALIAPAUL BANNISTER, CHRIS BLOOMFIELD1 Exergy Australia Pty Ltd, Canberra AustraliaABSTRACT: Water consumption in urban environments is a critical issue for a number of countriesworldwide. In Australia, a 5 year drought has left many city urban water supplies dangerously lowand led to significant water restrictions. Hong Kong similarly has limitations on its waterinfrastructure that affect the office sector. However, little is known about actual water consumptionin the commercial sector.This paper reports results of three separate studies into water consumption:Office building water consumption has been benchmarked for locations throughout Australia.Benchmarks have been developed on the basis of water consumption intensity measured in waterconsumed per m² of net lettable area. These have been implemented as part of a voluntary nationalwater rating system for office buildings which has achieved a significant impact in its first year ofoperation.Water consumption for cooling towers has been demonstrated to be a major driver of waterconsumption in Australian office buildings. The average water consumption per unit area of officebuildings more than doubles from the cool temperature to the tropical areas of the country.Water use in office buildings has been studied in more detail through the collation of water auditdata for a number of buildings in Sydney. The results indicate significant potential for improvementin water consumption, with leakage – such as through faulty toilet cisterns, urinals or faulty coolingtowers – being responsible for a significant proportion of average water consumption, in spite of fiveyears of increasing pressure to conserve water.The results indicate that there continues to be significant potential to reduce water consumption inoffice buildings in Australia. The results from Australia have application in many other countrieswith similar local or national pressure on water supply infrastructure, including Hong Kong andmany locations in China.Keywords: Water consumption, benchmarking, office buildings1. INTRODUCTIONWater consumption has become a defining environmental issue for the first decadeof the 21st century in Australia with drought conditions causing near-universalrestrictions in temperate areas and placing pressure upon infrastructure [1-3].The built environment, although dwarfed by agricultural water consumption (lessthan 15% of national consumption versus 65% for agriculture [4]), represents a166