Rainwater Tanks

Installing a rainwater tank is a great way for Hurstville City residents to conserve water. A rainwater tank can also save you money as it reduces the demand on mains water supply. The use of rainwater tanks decreases the amount of water going directly into the stormwater system during peak times, in turn reducing stormwater pollution and flooding.

Water collected in your tank can be used for watering the garden, washing the car, topping up swimming pools and washing machines and toilet flushing (if plumbed in).

Tanks with a capacity of 10,000 litres or less do not require lodgement of a development application with Council, however, they are subject to certain requirements.

Tank types

Rainwater tanks can be made of many different materials, including concrete, metal, fibreglass and plastic. Polyethylene rainwater tanks are the best option. Commonly known as 'poly' tanks, they come in many sizes and colours and are suitable for both above and below ground use. Poly tanks are durable, UV-resistant, light and easy to transport.

Above or below ground?

Rainwater tanks can be installed above or below ground. For the purposes of domestic rainwater collection and re-use in an urban area such as Hurstville City, above ground types are more suitable because:

  • leaks and cracks are easily detected
  • water can be extracted via gravity and/or pumps
  • tank s can be raised off the ground to increase water pressure
  • easily drained for cleaning
  • usually cost less than below-ground tanks.
Water use and tank size

The average person uses nearly 2,000 litres of water per week. As such the recommended minimum size tank is 2,000 litres. In an average household 1,000 litres doesn’t go far, equating to:

  • 1 hour with a sprinkler on the lawn or garden
  • 10 five minute showers
  • toilet flushing for two people for 10 days

Tanks come in many designs, and can be rectangular in shape, slimline for location against walls and under eaves of houses, or cylindrical. The shape and dimension of a rainwater tank for domestic use will depend on a number of factors including the location of the tank in relation to the house and property boundaries (boundary setbacks and impact on neighbouring properties must be considered). Other considerations include the roof catchment area, the number of people living in your house and your garden size.

Health and plumbing standards

A number of additional parts are required in conjunction with the rainwater tank in order to meet health and plumbing standards:

  • first flush devices – prevents the first portion of roof run-off from entering the tank, which reduces the amount of dust and leaves etc. entering the tank and polluting the water
  • screens and guards – stop debris and insects entering the tank
  • flow restrictor – ensures the water pressure supplied to neighbours is not affected when topping up your water from the taps
  • backflow prevention device – protects the water mains for contamination from backflow.
Cost

Apart from purchasing a tank, there are a number of other possible expenses required to install and efficiently run the tank:

  • delivery
  • installation
  • gutter, roof and downpipe alterations (for existing dwellings)
  • backflow prevention devices
  • a flow regulator
  • first flush device, screens and gutter guards
  • plumbing
  • maintenance
  • a pump (if needed)
  • a pipe to top up tank (if needed)

The approximate cost to purchase a 2,000 litre rainwater tank for a new dwelling, with the necessary health and plumbing standards, for a new dwelling is approximately $1500 if the tank is for external supply uses such as car washing and irrigation. If the tank is internally plumbed for use in the toilet and washing machine, the cost will be between $2500 and $3000.

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