Storage facilities differ according to their different purposes. Tanks are one of the most common ways of storing liquids. Tanks can be manufactured from different materials to achieve different aims, and to provide the most appropriate and cost-effective solution for storing a particular type of liquid. The most common materials used to manufacture tanks are steel, various plastics including polyurethane, and concrete. Each of these materials has its own peculiarities, advantages and disadvantages.

A Bladder Tank is one that uses a flexible bladder made from PVC, or Thermoplastic to store water or air. It is important to know how a bladder tank works in order to understand if it is the best solution for your water storage needs.

Each time water is used in the home, a certain amount of water leaves the tank. The more water that leaves the tank, the smaller it becomes. This leads to a drop of pressure in the tank. If there has been no rain to refill the tank, and the pump attached to the tank does not have a RainBank or RainSaver switch to automatically switch the water outlets over to mains water, then both water and air pressure in the tank will continue to fall. Some pumping systems used with bladder tanks will regulate the pressure inside the bladder so that it will not collapse to the point where the water is no longer easily accessible. Rainwater Tanks Direct sells bladder tanks that are contained in a lightweight galvanised steel frame to support the bladder and help it to maintain its shape.

In a densely populated urban area like Sydney, where space is limited, bladder tanks can be useful as water storage systems because they generally occupy space under floors and in basements which is not able to be used for any other purpose. However, when installing a bladder tank in Sydney attention should be paid to the following details: measure the available space according to the bladder tank manufacturer’s specifications; note the space the bladder will occupy when it is completely full; ensure that a clearance of at least 33 mms is available both overhead and along the sides of the bladder when it is completely full. The bladders sold by Rainwater Tanks Direct fill to a maximum height of 600mms. Note that an entry of at least one metre square is necessary to allow the bladder to be carried into and installed in the underfloor space.

As bladder tanks are usually installed in an underfloor space, ensure that the chosen area is perfectly level and smooth with no sharp objects such as stones or projecting nails. An installer will generally install the bladder in an area that has been covered with a sheet of heavy duty plastic to make sure that the site is free from debris which might damage the bladder. Remember that water is extremely heavy so all steps should be taken to protect the bladder from damage especially when it is completely full. The deflated bladder is then unrolled onto the plastic or tarpaulin, and/or into the frame, and the air vent screwed into the vent hole. Straps may be used to keep the bladder in place in the frame. The bladder is then ready to be filled and attached to the pumps.