What is the reason why the sewage pipe on the top of the underground garage drips?

The reason why the sewage pipe on the top of the underground garage drips is that the pipe leaks or the pipe is wet. This may lead to potential problems, such as soaking or corrosion, which need to be solved in time. Underground garage refers to a building built underground for parking motor vehicles of various sizes, which is mainly composed of parking rooms, passages, ramps or mechanical lifting rooms, entrances and exits, shunting yards, etc.