Our innovative Roof Water Harvesting System is a leading example of integrated water management.
We ‘harvest’ rainwater from rooftops that would otherwise go into the stormwater drain. Rainwater is a valuable resource and can support more liveable and sustainable cities.
In a natural catchment, rain falls on vegetation and infiltrates gradually. A lot of the rain in urban catchments covered by concrete, asphalt and carparks, can’t infiltrate naturally, causing high stormwater flows, scouring of waterways and flooding. Our harvesting scheme recognises rainwater as a valuable resource and reduces these urban run-off problems.
We’re very proud of this innovative scheme, a first in Australia.
How does the system work?
We collect water from the rooftops of:
- Homes in some north-east Warrnambool housing estates
- Sheds at the Gateway Business Park in Horne Road
- Buildings at the Albert Park sporting precinct
- Warrnambool College facilities.
A dedicated pipe system carries the water to Brierly Basin. We transfer it to the Warrnambool Water Treatment Plant for disinfection. It then becomes part of the city’s drinking water supply.
Each home connected to the system collects around 150,000 litres of water each year. This is roughly the same as the amount of drinking water they use.
Collaboration with council, developers and the construction industry was critical to the scheme’s successful introduction. We needed to establish administrative arrangements and support plumbers and builders to adopt a novel set-up.
Reducing reliance on the Otway system
Currently, 90 per cent of Warrnambool’s drinking water comes from the Otway Ranges. This means we need to pump it for more than 90 kilometres along our pipe network.
There are huge financial and environmental costs to pump water such a large distance. Energy is a significant cost and we’ve been working hard to decrease our emissions. We want to be net-zero by 2030 and ensure our systems are resilient to climate change.
Reducing our reliance on the Otway supply will help. That’s why we’re planning to expand the system across the north-east growth corridor over the next 30 years.
Eventually, the roofs of some 3,000 new homes will form an urban catchment. They’ll contribute 471 million litres of water each year to the drinking water supply. This will also provide future savings for our customers.
Preventing contamination
We need to ensure there is no risk of contamination to the system from sewage or stormwater run-off.
Each lot has a roof water harvest connection point near the boundary. Only downpipes and tank overflows can be connected to the system.
Water run-off from pavements and driveways must be discharged via the stormwater system. It’s critical that we maintain a clean system. You’re likely to see us in the area carrying out tests of the harvested water. We also do audits to detect any unauthorised connections or damage.
