During our daily practice of managing pests, we often are asked by customers “what are these flies always doing in my bathroom?”, and “I keep spraying them, but they always come back”. The simple answer is that they are most likely to be a drain fly.
There are a number of flies that can utilise drains for breeding, which is where they come by the common name ‘drain fly’.
The most common drain fly is the Moth Fly: these flies are fairly small, with hairs that are easily identifiable around the wings, and can increase their population to large numbers very quickly.
Recent treatment
We recently conducted a cockroach treatment at a unit in the area where drain flies were evident in the main bathroom and laundry. After asking our Amalgamated Pest Control technician about the flies, he explained what they were and how they could best be managed. Our technician then went back out to his vehicle, grabbed his foaming kit and completed another successful drain treatment, removing the problem completely for the customer.

Drain fly characteristics
The Moth Fly is possibly the most common drain fly found in domestic properties and very common at commercial properties. They seek out decomposing organic matter to deposit their eggs. Inside your home this matter exists inside common drains such as the shower, sinks and floor wastes, which is where the flies will lay their eggs. Once these eggs hatch, the larvae feed on microbiological organisms inside the dirty drains, grow into adults and fly up from there. This is why customers ‘keep spraying’ to no avail. While the hatched adult flies may be killed, the larvae are still hatching in the drains, feeding, growing and emerging as adults. Like many pests, if we don’t tackle the source, the problem will remain and continue.

How can I get rid of drain flies?
If you have a problem with the Moth Fly or any other species of drain fly, it’s recommended that you call in an expert to treat the problem for you. The only sure way to manage the problem is to directly treat the drain itself – going to the source!
This is done with specialised equipment, and a non-toxic biological agent. When combined with a foaming agent, the treatment will break down the decomposing organic matter within the drain which the Moth Fly larvae feed on. Cleaning the drain, leaving no available food source will control the problem as adults will seek other places to lay eggs. In most cases only one treatment will be needed, however in the more extreme infestations more than one treatment may be required.
The Drain Fly Solution
A special Foaming kit is filled with microbial concentrate and foaming agent. The Foaming kit is then hooked up to a compressor, and the drain is filled with the foam until it’s full. The foam pushes out the water and starts to breakdown the decaying organic matter inside the drain. The same process is undertaken with any connecting drains.
Once the treatment is completed, the matter in the drain that supports the larvae of the Moth Fly is gone, and these annoying flies are no longer a problem for you.
The procedure doesn’t take long to complete and can easily be carried out in addition to any other pest management treatments being conducted at your home. Just ask our technician on his arrival or our office staff when you book your treatment.
Still concerned?
If you believe or suspect that you have drain flies or any other pest problem, please contact your local team for further advice.
