Bladders are a great rainwater tank solution in areas where you face space constraints.
Installed in heavy gauge galvanised steel frames, bladders are sealed yet flexible water “sack” style units that are typically made from Aeon, an extra-strong material with enormously high puncture resistance.
Depending on their length and width, they can generally store between 2,000 and 20,000 litres of rainwater.
Bladders can be securely installed without excavation in your home’s sub-floor space in areas as low as 750mm in height. Importantly, they don’t add any structural load to your property.
Some people also choose to install their bladder under a deck.
Where space permits, multiple bladders can be installed end-to-end or side-by-side to maximise your water storage capacity. They’re typically designed to fill to a maximum height of 600mm.
One criteria to be aware of when choosing a bladder is whether it is filled from the top or the side. Bladders that fill from the side require less space for pipework overhead. However, if you have the space, an overhead filling configuration is fine.
Generally, you should divert all your downpipes to a common inflow-pipe which will feed into your bladder.
Your pipework should be plumbed so that any excess water is diverted to existing stormwater systems so you don’t need to worry about over-filling.
Compacted crusher dust, compacted cement-stabilised sand and concrete pads are all appropriate options for the ground beneath your bladder.
The area must be clear of rocks, tiles and other debris.
Before installation, smooth the ground, leaving a slight fall towards the bladder’s outlet end.
The right tank for you
If space is a key concern or you simply want to make greater use of your sub-floor area, a bladder may be the right rainwater storage solution for you.
Before making a final decision, however, we recommend that you calculate your ideal rainwater tank size so you can choose a tank or tanks that are appropriate for your water needs.
Or, to learn more about other rainwater tank options, check out this article.