Rainwater tanks

You don't need approval from the Department of Health to install or use a rainwater tank. But you should make sure the water is safe for human consumption.

You can get guidance about the use of rainwater tanks on the Australian Government's Department of Health website.

If you have a commercial or community facility that uses a rainwater tank you should find out how to manage private water supplies.

Rainwater is considered a high-quality water source with lower contamination risk than surface water.

However, this is not a guarantee of safety and contamination is not always visible.

To avoid or minimise water quality problems you can do the following:

  • Regularly clean the roof and gutters collecting rainwater by removing leaves, bird droppings and other organic matter.
  • After the dry season (Top End) or during cleaning of the roof and gutters, divert water from the first rainfall using a first flush or bypass device. This reduces the amount of contaminants entering the tank.
  • Remove overhanging tree branches that may drop leaves into gutters.
  • Paint or remove any lead flashings used in the roof construction.
  • Install screens on tank inlets and overflows to prevent the entry of leaves and small animals. Check the screens regularly.
  • Examine tanks for build up of sediments every two to three years or if sediments are seen in the water flow. Any build up of sediment needs to be removed (desludged).
  • Regularly inspect in ground tanks to ensure that they don't become contaminated. Water that has flowed over or through the surrounding soil or ponded on the lid must not be allowed to enter the tank.
  • Any nearby onsite wastewater management systems (OWMS) must be maintained and working effectively. OWMS effluent must not be allowed to enter drinking water tanks.
  • If the water supply has not been used for 24 hours or more, and water has been stagnant in pipes, copper or lead can build up. You should flush the pipes for a few minutes until fresh water flows through from the tank.

Different tank materials

Tanks built from different materials need to be treated differently during maintenance:

  • Plastic tanks need to be anchored when empty.
  • Concrete tanks should not be allowed to dry out in case of cracking.
  • Tanks with a ‘cone scour’ base are easily cleaned by opening the cleaning outlet to allow the water to drain out with the sludge, then rinsing with a hose.
  • Small, flat-bottomed tanks can be drained, rinsed with a hose, and tilted to drain.
  • In-ground tanks need to be cleaned and refilled quickly in case of tank displacement from the ground.

Rainwater tank

You should check all of the following every three months:

  • that there is no mosquito larvae in the tank water
  • inlets and outlets are covered to prevent mosquito entry
  • the strainer is clear of debris.

You should check the following annually:

  • the level of sludge and internal cleanliness
  • structural condition.

Roof and gutters

You should clean the roof and gutters every three months.

You should also do the following annually:

  • check and trim overhanging branches
  • inspect and repair downpipes
  • check the roof condition.

Last updated: 23 May 2022

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