The answer is: “Yes”.

While we have witnessed them, we are not experts on them. However, we found a lot of great info about this at:

Here is what we learned:

Drain Flies are very small (typically 2 to 5 mm in length), light grey or tan with short, fuzzy body and fuzzy, leaf shaped wings that live and breed in the organic matter present inside moist drains; hence they are mostly found in kitchens and bathrooms. They are not a harmful breed and do not transmit human diseases.

They are not very good at flying, don’t bite and can be spotted resting on walls and ceilings of infested areas. They can grow quickly and can multiply in a few days.

Before ridding your drain of flies, it is important to determine the infested area. Since they are not very good at flying, they typically stay close to their source. Look for the nearest drain in that area. If there are multiple drains in the area, you can cover them with sticky tape and see if there is evidence of them the next day (best to do at night because they are more active then). This will help pinpoint which drain they are living in.

There are great tips on this website to help find and treat these infected areas further.

Tips to keep your drains fly free:

  1. Keep the drains clean and clog free
  2. Make sure that there is no stagnant water in your bathroom or kitchen.
  3. Occasionally spray an IGR (Insect Growth Regulator) in your drains. IGR spray prevents the drain fly eggs from breaking out of the larvae stage and hence can greatly reduce the chances of any future infestation.