Water Neutrality

RHTC is committed to achieving water neutrality by 2030 while being resilient to water scarcity and extreme rain events
Water management is complex, dynamic and changing with our climate. As Australia’s climate becomes less predictable, we must enhance our resilience to reduce our consumption and conserve water in times of scarcity, but also to minimise the impact at Rouse Hill during floods and storms. 

To do this, we are focused on both the big picture and the supporting detail. GPT’s water policy sets an industry-leading commitment to achieve water neutral operations by 2030 and the Water Master Plan provides a roadmap as we gather knowledge, build resilience and offset our impacts. Our first step in the Water Master Plan is to define what ‘water neutrality’ means to us. We are gathering detailed information – from drawings to equipment documentation and sub-metering – to understand how water is supplied, moved, consumed, stored, polluted and released at site. We are examining the detail on everything from water consumption trends to contamination levels, rainwater collection to the velocity of water running into natural waterways during extreme rainfall events. This data collection phase lays the foundations for us to improve our performance over time. 
Rouse Hill Town Centre's approach to water neutrality is to maximise water efficiency, clean up and slow down stormwater and develop an appropriate program to offset our residual impacts on environmental flows of water.  Rouse Hill uses 32.5% recycled water with the help of a sophisticated system that captures, treats and re-uses non-potable water from several sources. For instance, we have located on site a 150,000 litre rainwater storage system that is fed from siphonic roof drainage to provide non-potable water for toilet flushing and for irrigation on the native landscaping throughout the centre.  In the 12 months to September 2022, this system saved almost 40 million litres of drinking-quality water – more than 15 Olympic-sized swimming pools. We also have a stormwater management system to reduce the amount of water being used in our activities and ensuring silt is captured with the use of silt bags and swales. Our water sensitive urban design minimises stormwater runoff, and our use of grassed swales and vegetation facilitates water filtration and the filtering of pollutants from all hard surfaces around the site. This in turn helps protect native flora and fauna and maintain a healthy ecosystem and community. 

Policy commitment 

Rouse Hill Town Centre is committed to achieving water neutrality by 2030 while being resilient to water scarcity and extreme rain events.  Our approach to delivering on these objectives is to:        
  • maximise water efficiency
  • drive the uptake of non-potable water sources (i.e. water that doesn’t come through the mains supply)
  • apply a ‘clean it up / slow it down’ mindset in reducing the pollutive and physical discharge impacts of stormwater

This approach is underpinned by a commitment to deliver projects and programs that don’t cause unintended outcomes, are practical and cost-effective (while looking beyond simplistic business case metrics) 

Water Management Plan 

To guide the delivery of our water management commitments, we have created an over-arching Water Master Plan for all assets, which is aimed at reducing the demand on water resources as well as the impacts of stormwater from our assets on downstream waterways.   
In developing our Water Master Plan we have identified the following three key pillars: 
Pillar Description 
Foundations The Foundations pillar incorporates all key elements needed to ensure our teams have sufficient information regarding our assets’ water infrastructure. 
Resilience The Resilience pillar focuses on managing the risks associated with a lack of suitable water supply and flooding that are either weather or asset induced. 
Water Neutrality  The third pillar, Water Neutrality, focusses on water efficiency, stormwater management and developing mechanisms such as offsets to facilitate water neutral outcomes. 

At the asset level we are creating site-specific Water Management Plans, with works already underway on the Foundation pillar for RHTC. 


Since 2005 we have seen a 62% improvement in water intensity. (Measured against GPT’s 2005 baseline as at 31 December 2022.) Detailed data and breakdowns are available in GPT’s Environmental Data Dashboard (view here), and metric definitions are available in the Sustainability Basis of Preparation and Glossary (Appendix C) fo the 2022 Sustainability Report (view here).The water performance of Rouse Hill is routinely assessed with the Sustainability Team on a monthly basis, with a more detailed evaluation conducted with the broader site team every three months.  In these quarterly meetings we review variances against year-on-year results and annual targets, interrogate sub-meter data, discuss any data transfer / integrity issues, discuss potential savings initiatives and formulate corrective actions where required. 

Water Efficiency 
Aside from the rectification of leaks / losses generated  by our monitoring program, we apply a very strong and on-going focus to water efficiency at Rouse Hill.  This is achieved through the considered selection of low water-using equipment, such as toilets, urinals and tapware in our amenities, along with drought-tolerant plant species in our vegetated areas.  We also target optimisation of  our cooling towers as an important aspect of our air-conditioning maintenance program, as these cooling towers, along with the Centre’s toilets, represent the largest uses of water in the operations of the asset.    
A key area for future focus will be to work more closely with our tenants to help support their endeavours in reducing water consumption within their businesses.  These reductions will not only lessen the draw on a constrained natural resource but will also lead to a decrease in applied outgoings, which will aid the financial strength of our tenants.  

Metering & Monitoring 

There are more than 120 water meters fitted at RHTC, covering both base building end-uses and a large number of tenancies. These meters are connected to the Building Control & Management System, which allows our Operations team to closely monitor the consumption profiles for these end-uses. The meters are also connected to our Envizi environmental platform that enables granular performance monitoring and reporting, as well as targeted alerts to be created for any of the following instances:
  • loss of meter data transfer 
  • out-of-hours consumption 
  • excessive water consumption beyond  

Our sustainability team conduct routine checks to ensure the integrity of the meter data is sound, with periodic validation exercises undertaken in accordance with industry protocols to flag any issues with the metering systems.

Non-Potable Water Supply 

There is an elaborate non-potable water system operating at Rouse Hill that combines recycled water from Sydney Water, rainwater harvested from the building rooftops and bleed-off from our cooling towers. 
Collectively, these sources have driven our proportion of non-potable water usage for 2022 to 44%.  In the 12 months to September 2022, this system saved almost 40 million litres of drinking-quality water, which is more than 15 Olympic-sized swimming pools! 

Stormwater Management

The development of RHTC incorporated a strong emphasis on the principles of Water Sensitive Urban Design.  The most visible form of these design elements is the bioswales located on Main Street, which provide a natural filter to minimise litter, sediment and other forms of pollution from  being discharged to the nearby Caddies Creek.