What do you have to do if you discover a floor drain in the basement, under the carpet, after you recently move in the house, and this one is getting really stinky and making the basement a no standing zone!?
Answer: There might be a partially clogged drain, collapsed drain. A good cleaning with a hose usually does the trick. Can be cap it with a test plug if is OK. But the best way is camera inspection with a mini camera and see if is still connected with main sewer line or with a sump pump pit. Either way is better first to see what will be in the future the room destination and for how many years, and make the decision after you consult a plumber.