iam not sure what is . clogged,My drains in my basement seem to be working. The drain outside my basement glass sliding doors has water standing in it.i have plunged and finally goes down just to return. i read a article says run water in sink if toilet bowl water rises its sewer drain.tried that did not rise I also have drain just to the right (if in front of house) of the one with water standing in it .Its like 5 feet to the right and if you go 4 feet behind that one there is one in my garage.I know the one that is 5 feet to the right is connected to the one with water in it,cause when plunge one with water ,water comes up over there but does not make one in garage overflow.My drain that is about 3 feet from my main is not over flowing so where can it be