Guidance on use of rainwater tanks

Preventing chemical contamination from on-site sources

Page last updated: March 2011

Chemical risks from on-site sources can be minimised by sensible management. Preventative measures can include:

  • ensuring that pipework in constant or prolonged contact with water complies with AS/NZS 4020, and is flushed regularly.
  • not collecting rainwater from roofs coated with bitumen-based materials or painted with lead-based paints
  • not collecting rainwater from parts of roofs that include exposed preservative-treated wood
  • ensuring that wood-based heaters and associated flues are designed, installed and operated in accordance with relevant Australian/New Zealand Standards
  • not using wood treated with preservatives or painted for fuel in slow combustion heaters
  • keeping the use of uncoated lead flashing to a minimum (as a precaution existing lead flashing could be painted)
  • replacing lead washers for roofing screws with plastic washers
  • inspecting tanks every 2-3 years for the presence of accumulated sediments and, if the bottom of the tank is completely covered, cleaning the tank
  • keeping gutters clean to prevent long-term retention of leaf litter and prolonged contact with rainwater. Gutter shields can be used to stop the collection of larger tree and plant material. Gutters should have a sufficient and continuous fall to prevent pooling of water. Prolonged contact of water with leaves can lower pH resulting in increased corrosion and the release of metals.