Filter fly or Drain fly are usually found breeding where rotten organic material can be found. More of a nuisance fly than anything. You are most likely to start seeing them coming from bathroom/kitchen sinks.
Grey/brownish in colour
Scales on the wings make them moth-like in appearance
Eggs laid in rotten organic material
Larvae hatch within 48 hours, Pupation in days, The average life span of 2-5 days
Filter fly will feed on organic rotten food in drains and pipes
Filter will live in and around drain pipes, the overflow
Reasons for control
Detecting an infestation
Detecting what and where your pest coming is from is key to any pest prevention.
If you are coming downstairs every morning to a fresh batch of droppings in the kitchen but have no idea where they come from, it could be a long while before you get rid of them. Identification is important, what to look for and to react quickly will greatly benefit you in the long term.