Water conservation

Tips to conserve water

Following are some hints about conserving water and tips about collecting rainwater.

An average person's water use

A household of 2-3 people uses about 225 cubic metres of water per year or 616 litres per day.

How water usage breaks down

  • A typical dishwasher uses around 16 litres of water per load
  • Summer gardens could drink 1,000 litres per hour
  • Washing your car with a running hose can use up to 400 litres
  • A deep bath can use more than 200 litres of water but a three minute shower uses only 80 litres.

How to save water

You can make savings on discretional water use - the non-essentials around your home and garden. Water savings are about preventing waste, like being careful with the hose and attending to leaky taps. The more water you save, the less you will pay. Here's a few simple tips to save you money AND save a little water.

In the garden
  • Hand watering is a very efficient way to use water
  • Water the garden only on calm days, during the evening or early morning to minimise evaporation
  • A wisely used timer or irrigation system can save water
  • A dripper pipe system is an efficient watering method. Moveable sprinkler systems are the least efficient method
  • Cover soil around plants with mulch, straw or grass clippings. This helps the soil retain moisture while discouraging weeds, which compete for water
  • Save 'grey water' for garden use
  • Don't hose down or 'water-blast' the yard or paths
Don't be a drip

A hose left running can waste up to 40 litres per minute - that's 2,400 litres an hour

A dripping tap can waste over 1,000 litres per day

In the house
  • Install water saving shower heads (less than 10 litres per minute) or flow restrictors
  • Keep bath levels to a minimum
  • Wait until you have a full load before using your dishwasher
  • Wait until you have a full load before using your washing machine or use the half load switch. You'll save as much as 125 litres per full wash.
  • When buying a new washing machine, consider a front loading type. They use less water, power and soap powder. You'll save around 50 litres per wash.
  • Insulate the hot water pipes, starting from the hot water tank and moving towards the taps
  • Don't use the loo as a waste bin
  • Turn off the tap once you have collected enough for the task, either in a bowl or in a sink with the plug fitted.

Flush facts

It's easy to reduce the amount of water used to flush the toilet:

  • Put a brick or a two-litre bottle of water in the toilet cistern
  • Install a flush saving device
  • Install a dual flush cistern when buying a new toilet or cistern. A dual system uses between three and six litres per flush

In the yard

  • Cover your swimming pool - you'll stop the water evaporating
  • Use a bucket and brush when you wash the car and the house windows

Collecting rainwater on-site for use on the garden or in the toilet system is a way to reduce the volume of water you require from the city supply.

Collecting rainwater

Collecting rainwater on-site for use on the garden or in the toilet system is a way to reduce the volume of water you require from the city supply.A diagram of a rainwater collection tank.

Reduce consumption

Roof water collected in a water tank can more easily be used for non-drinking purposes. About 30% of a home's water use is for toilet flushing and another 10% is used on the garden. By setting up a collection system for these two uses, you can reduce your water consumption by 40%.

The options for toilet and outdoor use of rainwater vary from simple 44 gallon drums under your downpipes for garden use, to complex systems involving pumps and filters. By raising the drums off the ground by about one metre (by buying or building a stand) the pressure head will be sufficient to operate a low pressure gravity fed irrigation system.

In both options, the outlet on the tank must have a sign to show that the water is not drinkable. A lid is also essential to stop insect larvae such as 

A diagram of a different style of rainwater collection tank. mosquitos from breeding in the water.

Supplies

Water tanks are available from plumbing supply shops. Sizes start from around 450 litres (100 gallons). Costs start from about $300.

We recommend you use the city water supply for drinking water. If using rainwater for drinking, you need to ensure the supply is safe by cleaning and maintaining the system, using filters or water treatment systems to control water quality.

More information

The Government has a useful website with helpful hints on water conservation as well as other tips on sustainable living: Click here for water advice from sustainability.govt.nz.