These traps are constructed outside the building to carry waste water discharge from washbasin, sinks, bathroom etc. and are connected to the nearest building drain/sewer so that foul gases from sewer do not come to the house. These are deep seal traps, the depth of water seal should be 50 mm minimum. It also prevents the entry of cockroach and other insects from sewer line to waste pipes carrying waste water.

Dry Manholes

It can be used to combine different branches of drainage lines to a single main line to the end of municipality connection.

Catch basins

It is usually used in garage area to protect the vehicle related waste from the municipality sewer line.

Sand trap

It is used to separate small rocks and sands from the drainage lines to avoid reaching at sewer line