How to Get Rid Of Drain Flies in Septic Tank

How to Get Rid Of Drain Flies in Septic Tank

The tiny moth-like bugs (drain flies) buzzing around your septic tank or drains are both a health hazard and a nuisance.

The moist conditions including the organic matter in the septic tank allow the drain flies to reproduce fast. But fear not, I’ll delve into ways you can use to get rid of drain flies in your septic tank.

Drain flies have a length of about 1/4 inch – they’ll love the organic matter in the septic tanks, bathrooms, sewage systems, basement, and near drains.

Details: How to Get Rid Of Drain Flies in Septic Tank

First, I’ll need you to understand the cause of these drain flies. These bugs thrive and reproduce fast in the septic tank due to the moist conditions.

Drain flies will inhabit stagnant water, pipes, and drains. So, it’s critical to solve the plumbing issues and septic tank moisture problems.

Check for moth-like, tiny bugs that will be near your septic tank and drains. The pests are brown, gray, or black – but there may also be maggots and larvae.

Step 1: Conduct an Inspection and Remove any Breeding Sites

First, I recommend you eliminate or remove those drain fly breeding locations. This location will have some decaying sewage and food, and other organic matter- which greatly encourages the breeding of the drain flies.

So, I recommend the process of cleaning the septic tank and drains around it – this will help eliminate the organic matter that would attract and host the bugs.

One method you may use will be cleaning these locations using drain cleaners such as Bio-Clean, Green Gobbler, or the Drano Max – these will help you flush out the organic matter that tends to build up in the septic tank and drains.

Besides cleaning the drains and the septic tank, you’ll need to eliminate other different locations where the drain flies to breed. Some of these probable areas include fixing those plumbing leaks, and dirty or clogged gutters.

  • So, inspect your spaces (drains, showers, toilets, gutters, or around sinks) using a flashlight to check signs of drain flies. Further, I recommend inspecting the outdoor sewage or drain systems.

Once you’ve pinpointed the flies’ breeding sites, you’ll require to fix the plumbing leaks, clean those gutters or drain out the standing water.

Step 2: Use Drain Fly Traps

After removing those drain fly breeding locations, next, you’ll want to use fly traps to get hold of any remaining bugs. Some of the approved drain flies include the pheromone traps or the sticky traps.

The pheromone traps employ some scented lure to attract the bugs. These trap’s pheromones are created to be like the natural pheromones created naturally by flies – and which they otherwise use in their communication.

  • The pheromones tend to attract the flies and hence they’ll get near the trap and they’ll get stuck on the sticky traps.

Sticky fly traps employ some sticky substance that’ll trap the pests. The sticky substance used in this tool is the trapping item. You’ll need to position the sticky drain fly in the right locations where the drain flies tend to land and breed most.

  • So, I recommend you place these traps near drains, toilets, and sinks – you’ll position them near breeding sites, ceilings, and walls.

Step 3: Apply Insecticide

For a massive drain fly infestation in your septic tank, I recommend you use some insecticide. You may use either foams, dust, or sprays. But for each, adhere to the product description and follow the safety directions such as eyeglasses and ensure the spaces are adequately ventilated.

  • This is an effective technique if the other DIY drain fly control methods fail to control the bugs fully. You may have pellets, foggers, or sprays.

I suggested you get advice from a professional exterminator or pest control technician – those that are near your residence or home.

Further, once you’ve applied the insecticide, you’ll require to sanitize or clean the spaces to remove the drain flies that are dead and also the residual chemicals.

You may use foam insecticides to treat locations that prove hard-to-reach like inside cracks, and pipes. The insecticide will expand to fill the deep gaps and thus they’ll suffocate the bugs.

  • The dust-form insecticide for drain flies will work by coating the object surfaces while also the chemicals kill the gnats that come into contact with it.

Step 4: Seal the Drains

Also, make sure that you keep great hygiene of your septic tank and the drains. This will hinder more of the drain flies from returning.

  • You’ll require to clean the septic tank and the drains – this will help to get rid of the organic matter – which would otherwise host the drain flies. In addition, cleaning the drain may also require you to employ bacterial treatments.

You must seal the septic tank and the drain to prevent their re-entry and breeding further. You may use a drain cover or plug for this.

  • Drain plus or covers may be of various sizes and materials including silicone, metal, or plastic – you can get them in the local home improvement shop or hardware.

Step 5: Hire Drain Fly Exterminators

Finally, if all the techniques outlined above have not helped to remove those drain flies from your septic tank, you’ll need to hire a drain fly exterminator.

  • The technician will come with advanced equipment and also expertise that’s targeted to specific pests including drin flies.
  • Such equipment will assist in the clear identification of the drain fly source and also in the efficient control of the infestation.

For the exterminator, you’ll prefer, to get one that is experienced in tackling drain flies and also well reputable from client reviews. So, I prefer you enquire for review from family and friends, especially with the local exterminators they’ve used.

Get the exterminator to inspect your septic tank, drains, and home in general for drain flies. This will assist in determining the level of infestation and hence knowing the treatment plan to employ – could be fumigation or insecticides.


Drain flies in drains and septic tanks can be a nuisance. These locations provide an excellent location for breeding – due to the organic matter and water – you can use exterminators, seal drains, apply insecticides, clean the breeding sites, and use drain fly traps.