• Really Group Concealed Rainwater Tanks Image
  • Really Group Concealed Rainwater Tanks Image
  • Really Group Concealed Rainwater Tanks Image

Concealed Rainwater Tanks

Blog post by Amanda Camilleri

Australia is the driest populated continent on earth, and yet Australians are the greatest per capita consumers of water in the world. Homes and gardens are directly responsible for about 12% of Australia’s water use. One change that all individuals can make to reduce their impact is simple, taking advantage of a free water source, rainwater.

Using rainwater can reduce your water bills, provide an alternative supply during water restrictions and help maintain green, healthy gardens. It can also help to conserve water resources and reduce environmental impacts beyond the home.

The graph below illustrates the average Australians household water consumption.

Water consumption in domestic properties

Water consumption in domestic properties

As conveyed in Figure 1, outdoor activities such as washing your car or watering plants consumes 58% of regular water usage in domestic properties. Water tanks are an excellent counter-balance for this fact.

The recycling of rainwater is not just limited to outdoor use. You can connect the system to almost all of your indoor household water activities including your toilet and washing machine.

Did you know an average roof size of 200m² has the opportunity to harvest, store and reuse up to 200,000 litres of rainwater every year. The average Australian water consumption per person is around 150 litres per day, or around 220,000 liters each year for a household of four. A 15,000 litre water tank has the opportunity to harvest 180,000 litres in a year, so for a relatively small investment its possible to capture almost all the water you need in your home.

Types of Concealed Rainwater Tanks

Large above ground water tanks are simply not compatible or practical in some urban areas where space comes at a premium, however there are alternative options on the market, such as underground, under deck and under floor water tanks.

Underground Rainwater Tank

These tanks are typically made up of concrete and you will need the help of professionals to have them installed. One good thing about underground tanks is that, they will not compromise any space since they will be situated underground. Concrete tanks are usually the most affordable for an in ground solution. They are ideal for this purpose because they can be covered with load-bearing lids and can fit under driveways or other structures.

Under Floor/Deck Rainwater Tanks 

Bladder tank: The bladders are sealed yet flexible, with an enormously high puncture resistance that is designed to be securely located in the sub-floor space or in areas as low as 750 mm in height. These types of tanks have the ability to collect all of the rain that falls on the roof by diverting the all downpipes to a common in-flow pipe which goes into the side of the bladder. This means that more rainwater can be collected much faster than in a traditional water tank. Once the bladder is full, any excess water diverts to the existing storm water system so that there is no fear of over-filling. The sizes and capacity vary according to length and width, the bladders can generally store between 2,000 and 20,000L of water.

Poly tank: Poly tanks are among the fastest growing types of tanks. They are made from polyethylene which is UV treated, impact modified, and food grade which means it is suitable for potable (drinking quality) water.


Moonee Ponds Development – Poly Underground/ Under deck Rainwater Tank

Benefits of concealed Rainwater tanks

Concealed water tanks are an ideal way to store water in an out of site location. Some of the benefits for using these types of water tanks are below:

  • Low in profile and unique in design and strength because they take on the concept of a slim line water tank along the side of a house and put it on its side.
  • Utilising wasted space
  • These types of water tanks are completely hidden and remain out of sight.
  • For most products on the market the raw powder used is UV stabilized so you don’t need to be concerned about plastic breakdown over the years and will last longer than a tank in full sunlight.
  • Depending on the setting you may be able to feed more downpipes to the tank than traditional rainwater tanks alongside a home.
  • Algae growth is almost non-existent, as sunlight traditionally cannot reach the inlets of these tanks.
  • Rainwater storage is completely enclosed so you don’t have to be concerned about water quality.
  • Ability to reuse
  • Quieter than tanks placed above the surface

Installing water tanks is only one way of reducing your impact on water wastage, visit our blog post for further tips on how to be more water efficient around your household.