Roof catchment
Z TSENZ
- Slovak term: Slovenský termín
- A roof catchment is a roof surface used for the collection of rain water for reuse. A catchment includes the entire roof surface within the catchment, the roof gutters, the roof down pipes, the roof drains and any rainwater retention and storage tanks (AusAID 2007).
Explanation
Roof catchments include the entire roof surface plus all the components use to capture and store the rain water. The roof materials must be compatible for contact with drinking water. Quality water harvested from a roof catchment can be improved in storage from a natural distillation process. Risk to water quality can be from airborne particles and from man-made air pollution.
A roof catchment will collect approximately 1 litre of water for every square meter of roof surface for every millimetre of rainfall (World Plumbing Council Working Group 2008).
Main points to consider when harvesting a quality and usable water from a roof catchment:
- Ensure the roof surface is of a suitable material for collecting quality rainwater, i.e. not corroded or likely to contribute contamination to the water on contact
- Ensure the roof gutters are installed to building standards and have fall to outlets to prevent ponding and sludge build up.
- Install gutter mesh to prevent leaves and debris from blocking gutters and mosquito mesh to seal the storage from insects and vermin.
- Fit gutter outlets to underside of gutter to reduce sludge build up.
- Fit rain heads to down pipes to ensure the maximum discharge is delivered to the storage.
- Fit a first flush by pass system to separate debris and sludge before storage.
- Draw water from the aerobic zone in the storage.
- Ensure the roof catchment is maintained and cleaned on a regular basis (WHO 2006, AusAID 2007).
Example
References
- AusAID (2007) Roof catchments and tanks for rainwater harvesting
- WHO (2006) Health Aspects of Plumbing
