As people’s awareness about water conservation increases, the growth in the water storage market has also risen. Traditionally, rainwater storage has meant large tanks which could only be placed on acreage properties. But now technology has advanced so far that water storage facilities can be implemented under concrete slabs in homes.
New Water has developed the In-slab tank. Andrew Pearce, chief executive officer at New Water, says typically, houses are built on a slab of concrete, with the concrete poured over the top of white polystyrene pods which are known as waffle pods. But instead of pouring concrete over the polystyrene pods, concrete is poured over the top of interconnected polyethylene pods by New Water.
The In-slab tank is around the same size as a waffle pod. Water from the product is pumped to various points around the home by a patented pump for use in the laundry, toilet, garden or for washing the car. Each pod has a 660 litre capacity, with the number of units which can be used only limited by the size and type of the concrete slab. Each tank is made of rotational-moulded polyethylene and has been tested to withstand the load of the concrete slab which is poured on top of the units. Each In-slab system is custom designed by New Water for individual dwellings.
The idea was developed around 12 months ago and was designed by engineers, with New Water creating several prototypes before the final product. “The difficulty was actually making sure that the pods could be connected together efficiently and easily and also to ensure that the design was structurally strong so it could actually withstand two tonnes of pressure,” Pearce says.
The materials used in the In-slab tank are the same that are used in standard rainwater tanks. “It’s just the way that the design works in terms of the angles, the thickness and the overall shape of it ensures that it has all the correct strength points,” Pearce says.
One of the main advantages of the In-slab tank is the retention of space which would have been taken up by external tanks. For example, in a townhouse development, legislation in places like Queensland mandate a rainwater tank. “You’d lose more or less your whole backyard,” Pearce says. “So instead, with this, you can actually put them in the slab and obviously you don’t lose any space.”
Price wise, Pearce admits they’re more expensive than a standard, freestanding tank. But he says they’re cheaper than in-ground tanks and equal out to around $1.00 per litre. The first project to use the product was a Hope Island home in Queensland. It used eight cells and has a total water storage capacity of 5,280 litres of rainwater.
The company has also been involved with a home in Sydney which used 18 interconnecting pods. New Water is currently looking at putting the In-slab tanks in commercial and retail sites and has an agreement with a builder that if one installation goes well, there may be the possibility of using the tanks in a further 150 new homes.
