This is something that puzzles me regularly but today I decided to really test it. So I have a bathroom in front of house, main bathroom even though it's mainly just the shower in there that is used. Anyway the drains run along the front of the house with a manhole at either gable and another one stupidly under the paving slabs in the porch outside this particular bathroom window. It can be accessed in emergencies but not easy!
Anyway if I lift the manhole at farthest end of house and flush toilet water goes through manhole, same if I turn on shower but if I run the sink no water appears in the manhole drain, the sink does empty, it doesn't appear to be blocked although it does get empty slower than it fills if you follow. Today anyway I filled it to the brim with very purple water (using up a bottle of old food colouring) and then pulled the plug and went out to watch the drain, absolutely nothing appeared.
Should it be draining in there? I can't imagine where else it should or could be going, where should I start looking to figure this out. There is no sign of damp patches anywhere either in bathroom or porch.
Anyway if I lift the manhole at farthest end of house and flush toilet water goes through manhole, same if I turn on shower but if I run the sink no water appears in the manhole drain, the sink does empty, it doesn't appear to be blocked although it does get empty slower than it fills if you follow. Today anyway I filled it to the brim with very purple water (using up a bottle of old food colouring) and then pulled the plug and went out to watch the drain, absolutely nothing appeared.
Should it be draining in there? I can't imagine where else it should or could be going, where should I start looking to figure this out. There is no sign of damp patches anywhere either in bathroom or porch.