How to Get Rid of Drain Flies at Home?

How to Get Rid of Drain Flies effectively

Moth fly (Psychoda sp.) is often called by several names such as filter flies, sink flies, sewer gnats and so on; however, the most common among the names is Drain Flies. As the name suggests, drain flies are usually found in areas where there is stagnant water such as drains. Mostly, people often mistake drain flies for the fruit flies. While a drain fly hardly causes any significant damage, when they come together in multitudes around or inside the house, their presence can be quite irritating.

Identifying Drain Flies

To recognise all the distinct features of a drain fly, a magnifying glass will be needed. However, you should be able to see the qualities below with your naked eye.

  • Light-coloured wings, and dark grey to black coloured body.
  • Long hairs on body and wings to form a fuzzy, moth-like structure.
  • Long and curved antennae.
  • 5-10mm long

Drain flies fly poorly and can only move in the air over a few feet at once. Hence, you can recognise them with their short, hopping flights once they are disturbed.

What causes drain flies?

To understand what causes drain fly infestations you first need to understand a little more about their behaviour.

They are usually found close to a water source or moisturised areas. They are small in size and light-weighted. Hence, wind can easily blow them from a drain to another sewage plant, which is about several miles away. Within residential areas, they can easily pass through standard screens with their small size.

Concerning their food, drain flies consume decaying organic materials in stagnant water, moss, mud, or flower nectar. They are capable of thriving and breeding in almost every place where there is an accumulation of organic material or stagnant water for at least one week.

Mostly, you will find drain flies:

  • In the house – In or near sink drains, windows and walls close to drains, floor drains inside garages, dirty garbage disposals, and rarely used toilets.
  • Outside the house – Around garbage areas, damaged septic lines, compost heaps, as well as stagnant water such as in ponds or objects that collect water when left outside.
  • Around nature – close to deep, dirty water or organic materials or compost with a high level of moisture.

Are drain flies harmful?

Due to their inability to bite or transmit any known diseases, drain flies rarely cause any damage. However, since they usually thrive in filth, there is a chance of spreading diseases. Furthermore, they can be nuisance pests. Especially considering that they can lay 10 to 200 eggs at once and it only takes 48 hours for their eggs to hatch. Consequently, their population tends to increase significantly within a short period.

Drain fly traps

If you intend to manage the outbreak of drain flies in your environment, then you have to find and eradicate their food and water sources. This is possible through the use of simple traps, which can be made with a plastic cup. Alternatively, you may use an insect glue board. Here is the how-to for the two methods:

1. Drain fly trap made with a clear plastic cup

  • Get a vegetable oil or petroleum jelly, then use it to coat the inside of the cup lightly.
  • Take the cup to the suspected drains and place the cup over the drain in an inverted position.
  • Allow the cup to stay for some days with daily checking. You will notice an accumulation of drain flies in the inner side of the cup if drain flies live in the drain.

2. An insect glue board as a drain fly trap

  • Make a cardboard frame to elevate the glue board over the suspected drain.
  • On the frame, place down the glue board in an inverted position.
  • Allow the board to stay there for some days with regular checking. If you see no flies after some days, remove the glue and place it over another drain suspected of harbouring drain flies. If there is no source within your apartment, endeavour to search the surroundings of your home.

Getting rid of drain flies..

After discovering the source of the flies, then it is time to eliminate them. If you want, you can remove the source or clear it off. However, keep in mind that complete elimination of drain fly issue will require consistent work.


  • Open the drains, drainpipes and sinks, then clean them all. Use a long, strong brush to clean the drains deeply. This is also a good way of cleaning a smelly drain.
  • Repair any faulty pipes or fixtures. Also, check for any leakage as it can attract these critters. You can easily identify a leak by hiring professional water leak detection services.
  • Check for any organic material and clear it. Clean the inside and surroundings of your rubbish bins.
  • Get rid of any other stagnant water or areas with high moisture such as stagnant water under a refrigerator, soggy spots close to house plants, or wet lint inside laundry room.


  • Get rid of any stagnant water around, ensuring that storm water drainage is adequate.
  • Clear and clean air conditioners, birdbaths, and garbage bins.
  • Clean up, removing any objects that collect water in your yard.

After a successful eradication of drain fly population, keep the area clean and free of stagnant water to avoid any similar problem in the future. For more ways to get rid of drain flies in your home, do not hesitate to contact the best plumbers in your local area!