If you reside or own a property outside of a city, you may need to carefully manage your water supplies. Rivers and dams bore water, and, most notably, rainfall is example of such sources. The majority of properties in semi-rural areas have a reticulated water supply. Nonetheless, water tanks are clearly something that can help create a sustainable water supply even in urban cities. This article will provide an overview of some requirements for installing rainwater tanks in Australia.
Rainwater Tank Systems and the National Construction Code
The National Construction Code (NCC) was recently adopted by Australian states and territories on 1 May 2016. It incorporates what was previously known as the Building Code of Australia (BCA) and the Plumbing Code of Australia (PCA). As such, Australian building and plumbing requirements are now found in a single code. The NCC can be found on the Australian Building Codes Board website.
Within the NCC is what is known as the “6 Star Standard” which are energy efficiency and water-saving provisions required in new homes and major renovations. Specific rainwater system requirements include:
- having a minimum rainfall catchment area of 50m2
- rainwater storage with a minimum capacity of 2,000 litres
- rainwater storage is connected to all flushing devices in all the toilets in the building in order to ensure use of the rainfall for sanitary flushing.
Installation of rainwater tanks must be compliant with the Australian Plumbing and Drainage standards (AS/NZS 3500). This generally means ensuring your overflow leads to appropriate stormwater drainage. Licensed plumbers are often required if the plumbing is in your rainwater, and certificates or inspections are required for interconnections with reticulated water supply since devices are installed to prevent your rainwater from flowing back into the pipes of your local water authority.
Additionally, the NCC requires that appropriate screening be used to protect rainwater tanks against mosquitoes and pests, which also helps to ensure maximum water quality in your tank.
While Australian states and territories look to the NCC for base requirements, you also need to be aware of any state and local requirements. We will specifically touch upon some requirements in the states of Queensland and New South Wales which Clark Tanks services.
Water Tank Requirements in Queensland
Unless your local Council stipulates otherwise, rainwater tank installation is a voluntary affair if you reside in Queensland. Unlike other states, there are generally no requirements that define a minimum tank size, roof catchment area, internal plumbing connections, etc.
In the past, new houses, and commercial and industrial buildings have been required to meet water-saving targets through rainwater tanks or grey water treatment plants. The Queensland State Government has in recent years updated these requirements such that if you choose to install a rainwater tank in a Class 1 building:
- a minimum roof catchment area of half the total roof area of 100m2 (whichever is less) is required; and
- a minimum capacity of 5,000 litres is required for detached buildings or a minimum capacity of 3,000 litres for all other dwellings.
Refer to the Queensland Development Code Part 4.2 – Rainwater tanks and other supplementary water supply systems (for residential – class 1, 2 and 10 – buildings).
“Class 1 buildings” are defined as any single dwelling (a detached house) or one or more attached dwellings separated with a fire-resisting wall, and boarding or guest house, hostel or similar with a total floor area not exceeding 300m2 and where a maximum of 12 people reside.
To ensure you comply with local requirements, we encourage you to inquire with your Queensland local council. We have put together an article specifically for the Gympie region, which you may find of interest irrespective of where you live in Queensland.
Water Tank Requirements in New South Wales
The NSW Government has implemented residential building requirements that aim to deliver sustainable water and energy, known as BASIX. BASIX assessment is required for:
- new buildings that consist of one or more dwellings
- conversions of an existing building to a building that consists of one or more dwellings
- additions and/or alterations to buildings that consist of one or more dwellings with an estimated work cost of $50,000 or more
- swimming pools with a capacity of 40,000L or more.
BASIX aims to achieve a 40% reduction in the consumption of potable water against the state benchmark. Rainwater harvesting systems are a great way to achieve BASIX certification for your proposed development. Rainwater collection is assessed based upon:
- the capacity of the rainwater tank being installed
- roof catchment area that will be connected to the rainwater tank
- how the tank water is used
- running overflow from your rainwater tank to another tank for collection and re-use.
In NSW you must also comply with the development regulations articulated in the State Environmental Planning Policy. Many specific requirements are provided depending upon whether your rainwater tank is installed above or below ground. Some of these include:
- plumbing your tank into your house and/or interconnecting to mains water needs to be carried out by a licensed plumber
- your water tank cannot be placed on the footing of an existing building
- screening against mosquitoes and other insects breeding inside is ensured
- the overflow of the tank is connected with an existing stormwater drainage system
- the water tank is placed in the rear yard, behind the building line
- protection against vermin entering the water tank is ensured
- protection against ingress of stormwater and groundwater if the tank is partially or completely buried in the ground is ensured.
Please note, that these serve as foundational requirements in NSW. You may also have additional requirements set by your local council. We have put together specific requirements for Wagga Wagga and the Tamworth Region that you might find of use.