A catch pit is an empty chamber that is installed into a drainage system to prevent silt and debris from building up and causing blockages.
Wastewater flows into the catch pit through an inlet pipe that is always raised above the floor level of the pit. Any sediment in the wastewater will settle at the bottom of the catch pit over time, where it can be periodically pumped out and removed from the system.
Water flows out of the catch pit via the lower discharge outlet. Many catch pits are pre-fabricated, either from pre-cast concrete or thermoplastics such as high density polyethylene (HDPE).