Part B1 Cold water services

(2) For a new Class 1 or Class 2 building, in an area serviced by a Network Utility Operator water supply, toilet cisterns must—

1. have a dual flushing mechanism; and
2. be a minimum 4 Star WELS rating discharging not more than 4.5 litres for a full flush; and
3. are compatible with the size of the toilet bowl to allow for proper functioning of the toilet.

For all other installations, cisterns or flushing devices for water closets must—

1. have a dual flushing mechanism; and
2. be a minimum 3 Star WELS rating discharging not more than 6 litres or 4.5 litres for a full flush.