Water

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

Materials

Use only materials that will not contaminate the water when collecting rainwater for consumption purposes. Roofing, spoutings, downpipes, storage tanks and pipework materials must comply with AS/NZS 4020 Testing of products for use in contact with drinking water.

Find out about:

  • roofing
  • roof paint
  • gutters and downpipes
  • storage tanks.

Roofing

Roofs suitable for water collection for human consumption include:

  • unpainted zinc/aluminium coated or galvanised steel
  • factory-coated or painted zinc/aluminium alloy-coated or galvanised steel
  • zinc
  • stainless steel
  • aluminium
  • concrete or terracotta (clay) tiles
  • copper
  • PVC (without lead stabilisers) or fibreglass sheet
  • untreated timber shingles (usually imported western red cedar)
  • butyl rubber.

Leave a new roof for at least one good period of rainfall before connecting the downpipes to the storage system.

Do not use collected water for drinking if it has come into contact with:

  • uncoated lead flashings (lead flashings on existing roofs should be coated with a suitable paint; coated lead is available for new roofs)
  • treated timber where chemicals leaching out might contaminate the water
  • bitumen-based roofing
  • asbestos (although no longer used in building, existing asbestos roofs should not be used for collection of rainwater).

Roof paint

Specify only paint that the manufacturer recommends as suitable for collection of rainwater for drinking.

Do not use collected water for drinking from roofs coated with:

  • lead-based paints
  • bitumen-based paints
  • acrylic paint until it has been washed by a good rainfall.

Gutters and downpipes

Materials suitable for use for gutters and downpipes where potable water is being collected include:

  • extruded PVC
  • factory-coated zinc/aluminium alloy-coated steel
  • galvanised steel
  • copper (may cause staining if water has a low pH)
  • aluminium
  • polyethylene/polypropylene.

Storage tanks

Suitable materials for water storage tanks include:

  • galvanised steel
  • fibreglass
  • plastics such as polypropylene
  • concrete
  • ferro-cement.

Tank materials should not transmit light, as light will encourage organic growth.