PURPOSE: To obtain a changeover socket for changing over drainage paths in prepared waste water treatment facilities for emergency when the drainage paths of a public toilet in a park, etc., are damaged by an earthquake, etc.

CONSTITUTION: A changeover socket for a drainage path is formed in structure having a bottomed vertical cylinder section 2 having an opening in an upper section, an on-normalcy duct 3 protruded from the vertical cylinder section to the left and the right so as to be communicated through the vertical cylinder section 2, an on-emergency duct 4 protruded in one direction from the vertical cylinder section 2 on the lower side of the on-normalcy duct 3, a closing door 5 closing the on-emergency duct 4 from the vertical cylinder section 2, and an operating means 6 for pulling up the closing door 5 to the upper side through the opening of the vertical cylinder section 2. When the closing door 5 is pulled up by the operating means 6 at the time of emergency, the flow of waste water is changed over from the on-normalcy duct 3 to the on-emergency duct 14.