Water

Designing homes to use water efficiently, reduce costs and cope with more frequent droughts or storms.

Greywater recycling

Recycled greywater:

  • reduces the load on sewerage systems including on-site treatment systems
  • provides a garden irrigation water supply
  • may be used for toilet flushing if treated to minimise growth of micro-organisms in the cistern.

Find out about:

Safety considerations

Greywater recycling must be designed and installed with care as it is potentially unsafe in some situations. To reduce risk, greywater used for garden irrigation should deliver water below the soil surface.

Some local authorities in New Zealand encourage greywater recycling, but other authorities do not.

The Ministry of Health considers that it carries potential health risks and does not support greywater re-use in homes.

BRANZ does not recommend greywater use for:

  • washing clothes
  • garden irrigation by sprinkler
  • use on vegetables or salad plants.

Collected rainwater is a preferred option for toilet flushing than greywater.

Greywater systems must be designed so that, if the irrigation system is overloaded by heavy rainfall or surface flooding, the wastewater can be discharged to a sewer or on-site blackwater treatment system.