Underground

• Measure the available width and length of the area where it can be installed (assume that a width of 2m x 5m is available in your back yard).
• Divide the available area into the required capacity to get the optimal low profile underground tank height in millimetres Assume the required capacity is 10,000 litres. The area is 10m² (2m x 5m). Capacity of 10,000 litres divided by 10m² = 1,000mm (or 1m).
• If the tank is generally accessible, a lockable lid should be installed Check with the manufacturer to ensure a lockable lid option is available
• if the tank is to be installed in a trafficable area, the collar and lid f the tank should be certified to be load bearing Check with the manufacturer to ensure that the an option for a load bearing lid and supporting collar is available
• Choose the underground tank that most closely meets the above criteria

• Ensure that the underground tank manufacturer is a company that is accredited to the Australian Standard for Poly Water Tanks (AS4766).
• Ensure that the underground tank is compliant with the Australian standard for septic tanks (AS1546.1). This is critical to ensure that an underground tank can withstand the weight and forces associated with being buried.
• Where possible, ensure you install the lowest profile underground tank to minimise the cost of excavation:
• An excavation deeper than 1500mm (1.5m) must be fenced or the sides of the excavation must be "shored up" (Worksafe’s Working at Depth Guidelines (Mines Act - Trenching) 1982).
• If the underground tank will be generally accessible once installed, ensure that the option of a lockable lid is available for the obvious safety reasons. if the underground tank will be installed under a load bearing area, ensure that the option of a lockable load bearing lid is available
• Underground tanks should always be accessible for any on-going maintenance. the man hole in the water tank should be large enough to install and remove submersible pumps and to remove sediment from time to time. Waterplex recommends a minimum manhole access of 300mm in any underground tank

The interconnection foot on each of the underground tanks is also the foundation of a retention / detention system. By drilling a hole to match the specified discharge rate (i.e. orifice plate) through the interconnection foot, positioning the overflow pipe at the desired storage level and linking this with the barrel filters overflow a simple, effective 100mm retention / detention system can be created.

If you have any questions about the selection or installation of an underground tank, call the team at Waterplex on 1300 72 66 70.

Underground tanks from Waterplex can be used to store water in the following capacities by combining multiple tanks. For larger storage requirements, contact the team at Waterplex on 1300 72 60 70:

Underground Water Tank Capacity Configuration