Rainwater and greywater

Saving water for a not-as rainy day.

Rainwater tanks

Rainwater tanks are popular for saving water. Tanks are easy to use and available in styles to suit most homes. 

  • Collecting rainwater allows you to be prepared for times of low rainfall, so you can still maintain your garden, especially if there are water restrictions in your area. Permanent Water Saving Rules do not apply to the rainwater you catch.
  • Your garden loves rainwater. You can also use it to top up your pool or to wash your car.
  • Using rainwater can reduce your water bills as rainwater is free. You can have your tank connected to your outdoor taps or even plumbed into your toilet or laundry. Toilets use approximately 14 per cent of drinking quality water in the house and washing machines use around 16 per cent.
  • Tanks plumbed to the toilet and laundry can be used effectively during periods of high rainfall when you don’t need to water your garden. By connecting a tank to the toilet or washing machine with a switching pump you can use your tanks all year round. When tank water is available, the pump uses it and automatically switches to mains water when the tank is empty. You should speak to a plumber about making these connections.
  • Tank water should be used in preference to greywater, especially for herbs and vegetables. Even better, use tank water in conjunction with other recommended water-saving measures like mulch, drip systems and soil additives. If you are in the process of planning a new house think about ensuring the design includes provision for a rainwater tank. At the planning stage you can arrange for a suitable space for your tank, including underground and bladder style tanks for under your decking. You will save water and add considerably to the value and enjoyment of both your house and your garden.
  • Capturing rainwater reduces the load on stormwater systems because roof runoff is not flushed into the drains. Rainwater helps reduce stormwater damage to creeks.
  • Using rainwater reduces the amount of mains water taken from natural waterways and the need to build more water storage dams, which may have to be situated in environmentally sensitive areas. 

Using greywater

Greywater is a great option for your garden watering because most people have a plentiful supply, it doesn’t rely on rainfall or vary much with seasons and it reduces your reliance on potable (drinking quality) water.

All the water that comes out of the tap is top quality drinking water, but not all of the activities that we use water for around the house need drinkable water. Greywater is the used water from the bathroom, laundry and kitchen. It doesn’t include water from the kitchen sink or from toilets (known as black water).

Using greywater for flushing toilets or on your garden is a great way of being water efficient but make sure you seek professional advice in doing so as it may contain disease causing organisms. The general advice is not to store greywater for any length of time but to use it immediately for its purpose eg put it straight on the garden.

Water can be recycled from your shower and washing machine but because it contains some bacteria, detergents, cleaning agents and waste material, it isn’t suitable for all garden uses.