← Back to Glossary Index

This is where the storm water from the roof and the groundwater is piped to a holding tank, usually buried in the ground or under a deck. This tank can be anywhere from 3,000 to 20,000 litres and essentially slows down the water flow to a more manageable level as it enters the public storm water system.

While the inlet is any size according to your roof area, the outlet is just 25mm. This means the water is drained slowly over a greater period of time rather than during the immediate downpour.