Bathroom Flies

29 March, 2009

A Bathroom Fly, <I>Clogmia albipunctata</I>
A Bathroom Fly, Clogmia albipunctata
Image: Michel Vuijlsteke
Source: Michel Vuijlsteke

Question: I have a problem with large numbers of small flies in my house. Can you tell me what they are and how to get rid of them? They are easy enough to catch, but there are many more each day. They are mainly in the bathroom so I wondered whether they are attracted to water.

Answer: Thank you for sending your insect image into the Discovery Centre at Melbourne Museum for identification. The flies in your bathroom are from the family Psychodidae and are commonly known as bathroom flies, moth flies or drain flies.

These dark grey flies are 2-4mm in length and have hairy moth-like wings. They have a jerky flight and are observed around bathrooms, in damp subfloors, in greenhouses and in other locations where moisture and the presence of decaying organic matter will support their presence.

If you are seeing large numbers and you don’t regularly leave your windows open, the flies must be breeding inside your house or in your water pipes. You could have a drainage problem, such as slow-draining pipes, or water pooling in over-watered pot plants. Once you remove all permanent sources of water and fix any drainage issues, the flies should disappear.

Bathroom flies are not harmful to people and will not damage clothes or linen. They are therefore considered to be of nuisance value only.

Comments (20)

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mia sotto 22 September, 2009 01:11
Hi! There's an annoying insects living on our bathroom a fly look alike. There's like a thousands of them. I keep on getting rid of them everytime i take a bath. But it seems they don't disappear. I' m so much bothered because i have a 9 month old sister, she might swallow one. Can i use pesticides or something? How can i get rid of them? They look so disgusting when they are all together. So lots of them! Please do reply. I really need to get rid of them so badly. Thanks!
Itzely 22 June, 2017 23:07
I also have the problem
Discovery Centre 22 September, 2009 13:58

Hi Mia. We think that the infosheet above should give you the information you're asking about. These flies are called drain or bathroom flies. They breed in water, so you may have an drainage problem that you need to fix, rather than using pesticides. If this doesn't work you might wish to contact a professional pest controller. The insects are not harmful to people or clothes.

Sarah 23 October, 2009 12:03
Hi. In the office where I work there are a lot of little flies, which I think might be drain flies. We only have a kitchen sink in here and 1 pot plant so I'm not sure if they are drain flies. We don't have fruit or vegetables in our office and we empty the rubbish bins often, the only thing I can think of is that we are right next door to 5 food retailers so maybe they are coming from there or could it be weather related? Its hard to see as they are about 3mm long but it looks like they have stripes on their back. Sometimes bite/make you itchy. Do you know what they could be or how to get rid of them. Thanks
Discovery Centre 24 October, 2009 11:47

Hi Sarah,

We can definitely have a go at identifying your flies, but we would need at least an image of them first, if not a specimen. Should you be able to capture and image or specimen, please feel free to lodge an identification request with the Discovery Centre here. Once we know what they are, we can then offer information about their behaviour.

sally bugg 6 November, 2009 16:43
do those drain flies turn into worms?i think i swallowed one. and i saw some in my dogs water dish ...
Discovery Centre 9 November, 2009 17:29

Hi Sally,

In answer to your question, bathroom flies do not turn into worms. Once the flies pass through their larval stage and emerge as adult flies that is the form they retain until they die. Even if you managed to ingest a bathroom fly I doubt that one fly would do you any harm.

shane 19 November, 2009 02:43
hi in summer time and warmer nites as i sit in my lounge room i get biten by was it seams like baby flys i cant feel them bite me but can se them sometimes then after there bite go like mozze bites and itch like crazy some of the bite last for weeks can you please help tell me what they are and how to contol them thanks shane
Discovery Centre 19 November, 2009 10:03

Shane - Museum Victoria offers a free identification for insect species. Requests can be lodged at this part of the website. If you can't provide a clear photograph you'll need to send a well-protected specimen via the post. See these guidelines for further info. Hope this helps!  

Jeanette DeLucia 4 May, 2010 07:35
I have small flies (alot of them) that seem to just hover in my patio area that has a roof but no walls. Could this be the same as the bathroom flies? They are driving me crazy, when I open my patio door they get in the house. Any suggestions? There no way to stop the moisture out side.
Discovery Centre 5 May, 2010 10:18

Hi Jeanette, Museum Victoria has a free identification service.  If you are able to collect some of the flies you can either bring them in, or post them in and we will have the entomologist take a look for you.  Unfortunately we cannot offer advice about pest control, but once you know what they are you may be able to make some simple changes at home to eradicate them.  Information about the identification service can be found here:

amber mcvay 1 September, 2011 13:13
i think we may have these drain flies. i never seen them before untill last summer and this summer and they are small and black they look like the pick posted above but they are not fuzzy looking an dwhen i kill then they look like litte spots of dirt once i swat them! but they r in most of the room except up stairs??
dejavu 31 January, 2012 22:43
hi, this bathroom flies/moth flies are in my bathroom. They keep multiplying every day as i try to get rid of them. The point is that when i occupied the apartment, they where not there and suddenly boom, they start appearing. Nothing changes except the weather, could that be a cause?. I need to get something to get them off my bathroom. Please help with a solution, pesticide, insecticide anything. Thanks.
Discovery Centre 1 February, 2012 10:50

Hi dejavu,

Please see the answer given on 22 Sep 2009.

Nina 9 February, 2015 00:35
Hi there, we have those bathroom flies in our house and one bit me just then and the bite is getting bigger like when you are allergic to mozzy bites. And it itches like hell. Is it dangerous? Thank you.
Dana 23 March, 2015 00:02
Hi Nina The same happened to me It was a painful bite and developed into a welt and after that I also felt itching They all say they don't bite but I'm sure I was bitten I sent a photo to the museum It's possible we are sensitive to it
Dana 22 March, 2015 23:58
I believe I was bitten by a Sewer / Drain Fly and it was very painful and the bite turned into a welt and didn't ease for over a week I submitted a photo of it to the museum
Trish 17 September, 2015 15:14
Hi, Do these flies bite? Sometimes when I squish them there is blood.
Jung suman 9 January, 2016 18:50
I am from victoria,recently living in queensland .its very humid here,i am having a problem with very small fly like drain fly .they are even smaller than drain fly and always bites us,and its really itchy.they enter through window even through insect net.they are driving us crazy ,any solution to get rid of them will be help ful...
layla 10 October, 2016 13:40
I found some drain flies in the toilet, the shower, and in my dog's water bowl, so i was wondering if you had any suggestions on how i could get rid of them. And if this means they are in the water that we drink and bath in.
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