Question

where does the water come into the tankand where does tje excess water go

Answer 1

A rainwater tank called a rain barrel in North America in reference to smaller tanks, is a water tank used to collect and store rain water runoff, typically from rooftops .Rainwater tanks are devices for collecting and maintaining harvested rain.

Answer 2

store rain water with help of sinking pit and typically from root tips rain water devices for collection of harvested rain water