The use of rainwater for WC flushing: the field testing of a collection system

The flushing of toilets with rainwater collected from roofs makes a significant saving in the use of potable water. This paper describes some of the results from field testing a rainwater collector installed in a U.K. house. The capacity of the storage tank is critical in the design of such systems. The data collected was used to verify and refine a rainwater collector sizing model. The model was used to produce a set of dimensionless design curves which enables the storage capacity required to achieve a desired performance level to be easily determined if the roof area and demand patterns are known.