Yes the tiny flies in your bathroom are drain flies

Last week Lynette, who is one of our Service Partner clients, sent me a photo of her bathroom floor enquiring whether I knew if these tiny flies seemingly coming out of her bathroom drains were drain flies. My simple reply was yes as they are more prolific in spring and summer when temperatures exceed 20°C.

The photo above is dramatically magnified to illustrate the number of drain flies in a small area.

Lynette was concerned that no matter how many times she sprayed the flies to kill them, there was always more flies the next day. In fact, what disturbed Lynette the most was that they just appeared to multiply and accumulate on the walls and floor but only in the one bathroom. The flies were nowhere else in her home or in the other bathrooms.

Cleaning your bathroom won’t eliminate drain flies

Lynette was exasperated and frustrated that no matter how often she cleaned her bathroom, the drain flies just kept returning and multiplying.

She repeated to me what I’ve heard multiple times over the years, that she would clean the bathroom with a powerful supermarket bleach cleaner and by the next day the drain flies would have returned.

A friend had told her to buy a 2.5-litre container of bleach and pour it into all her drains in the bathroom which would kill the flies within 24 hours. After using all 2.5 litres of bleach the drain flies were still there.

What are drain flies?

Drain flies are more annoying than anything else as the sheer numbers in your bathroom are unsightly creating, an illusion that the bathroom is not clean.

They do not bite nor do they transmit any diseases of any sort. Nor do they damage clothes, towels or linen. 

Drain flies are prolific breeders which is why people like Lynette get frustrated as the more she appeared to kill, the more prolific they became.

The flies themselves are only around 3-4mm in length being dark grey in colour with hairy moth-like wings which as you can see in the photo below dominate their body size.

Are these tiny flies coming out of my bathroom drains drain flies? 3

Why do drain flies only appear in bathrooms?

If you don’t live on an acreage block with a septic tank or sewer treatment plant, then the only place you will probably experience drain flies is in a bathroom. In septic tanks of sewer treatment plants drain flies breed prolifically but don’t stray far from the tanks which are their food source.

In bathrooms, the flies during the day appear to do nothing other than just sit on walls or under the vanity basin or on the ceiling. This is because they are more active at night, which is why you will seldom see them flying or actually emerging from you floor waste drain.

Even though they are poor fliers the flies are frequently transported by the wind away from septic tanks or sewer treatment plants for distances of 3-5km. This can allow them to enter your home through your insect screens as they are small enough to get through the holes in the mesh. Ultimately they will search for your bathroom floor waste drains because this is where they can feed and breed.

Where do drain flies live and breed?

Since drain flies are such poor fliers, they will always be found within a few meters of the bathroom floor waste drain. This is why you only ever appear to see them in a bathroom.

Infestations occur once temperatures exceed 20°C in spring. The rationale that they keep multiplying is not misplaced as their life cycle is 1-3 weeks from eggs hatching to becoming adult flies. They are prolific breeders with eggs hatching within 48 hours to become larvae. The larvae then mature within 12 days feeding on the decaying organic matter in the bathroom floor waste drain. The adult flies emerge from the drain at night that you then see on your bathroom walls and ceilings will live no longer than 2 weeks.

How you can eliminate a drain fly infestation in your bathroom?

Controlling and eliminating adult drain flies and larvae is by eliminating breeding sites in your bathroom drains. The pouring of bleach into the floor waste trap will typically work if you have a minor infestation.

A major infestation will not be solved by bleach as you need to thoroughly clean the and seal the floor waste trap to eliminate their food source and breeding ground.

From experience, we have found cleaning the whole area around the floor waste and inside the drain with Aquatemp Surface Sanitiser & Disinfectant will clean and disinfect the drain flies breeding ground and food source. 

If you are experiencing the annoyance of drain flies that will not go away give us a call at Whywait Plumbing on (07) 5551 5193 to book a service call so we can eliminate them once and for all.

Aquatemp Surface Sanitiser & Disinfectant 1 Litre Spray Bottle $36.92

Aquatemp Surface Sanitiser & Disinfectant comes in a ready to use spray bottle that eliminates the drain flies food source and breeding ground effectively plus sanitises, disinfects and protects for up to 24 hours.

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