Newbie here so apologies if I am posting in the wrong section. In the last two weeks in our downstairs bathroom we have been encountering 5-15 tiny black flies. Very puzzled as to where they are coming from.

My husband has thoroughly cleaned out the whole room, even taking the trap off the sink in case they were breeding in there.

As a final resort on Sunday he took the cover off the washing machine and cleaned the trap out on that and ran vineger through the machine. Took the hose out of the standpipe and poured some enzyme based cleaner in the hose and the standpipe. Covered it with tape for three days and no bugs.

Today we took the tape off and ran two loads of laundry. Low and behold tonigjt we are encountered with bugs again.

Is it possible bugs are breeding in the machine or in the standpipe. I would not think so given the water pressure flowing through there. If so is it possible to clean the standpipe out or pour drano down there to clean out.

At our wits end as to what to do here. Had thought about the pest person but worried they will spray which will clear it for a few days and they will be back again.