BASIX requires the applicant to enter in the rainwater tank size. It is recommended that the available rainwater storage is kept to a maximum by installing any drinking water supply top-up valves within 300mm from the base of the tank. If you require a greater top-up level, it is recommended that this volume is provided in addition to the size nominated in your BASIX commitments.
Local council authorities may require rainwater storage tanks for the sole purpose of fire fighting. This cannot be included in BASIX. The rainwater tank size nominated in BASIX must be in addition to this requirement.
When determining the size of a rainwater tank the following considerations should be made.
|What needs to be considered||Appropriate action|
|Available Land Size||
If you enter rainwater tank larger than a maximum allowable size, BASIX will advise you to consider the selection by not allowing certificates to be generated. Increasing the size of an already large tank may not result in proportionate improvements in potable water savings. It may be more cost effective to consider other water efficiency measures than increasing the rainwater tank indefinitely.
You can enter the maximum allowable size as advised by the BASIX tool, but still install a larger tank on site. Since the BASIX certificate states that "The applicant must install a rainwater tank of at least [number] litres on the site", the larger tank is regarded as over-complying with the BASIX requirement.
There are a variety of rainwater tanks types available and due consideration should be made when selecting the appropriate tank type for each site.
- Metal/Steel Tanks
- Concrete Tanks
- Plastic Tanks with Plastic Liners
- Fibreglass Tanks
If a rainwater tank will be located in a bushfire prone area, the tank should be fabricated from steel, concrete or other suitably protected material in accordance with NSW Rural Fire Service guidelines - NSW RFS website). Durability of other components should be confirmed with suppliers and appropriate warranties obtained for tanks and other system components.