When I was renting a condo unit, I never had to deal with drain flies. But ever since I bought an HDB flat, they seem to want to share the flat with me. After trying another blogger’s method on how to get rid of them and then trying an all-natural method, I found an even better way. One that is not only easy, but also non-toxic and cheaper in the long run. 

The First Attempt  the shotgun approach

I followed the steps that the blogger published. Similar steps were also mention in a popular home renovation site. The “weapon of choice”, as the blogger put it, was to use moth balls containing naphthalene.

You can find naphthalene balls at NTUC. They are relatively cheap at $1.50 for a 250g bag. BUT… I wouldn’t recommend it.

I tried it. And yes, they will eliminate your drain flies. But they smell awful. And that smell spreads and lingers throughout your home. Even if you put a cover on them.

But what’s worse is that they are not just toxic to drain flies, they are toxic to humans too. According to the US Environmental Protection Agency, acute exposure “to naphthalene by inhalation, ingestion, and dermal contact is associated with hemolytic anemia, damage to the liver, and, in infants, neurological damage.”

And since the moth balls sit on top of water drains, they eventually can seep into our water supply. According to the US Centers for Disease Control, naphthalene is “very toxic to aquatic organisms [and] may cause long-term effects in the aquatic environment.” This is especially concerning in Singapore, since many of us drink recycled water.

So I decided to look for a more natural approach.


The Second Attempt – a more natural approach

A less harmful way of getting rid of them involves cleaning your drains regularly with baking soda and vinegar. This article from Mother Nature Network shows you how.

But because you can never fully eliminate them from the shared HDB drain, these pesky flies eventually come back. For me, they were only gone for one week.

I figured that in any given month or year, I would be wasting too much baking soda and vinegar, and I didn’t feel right just (literally) throwing these things down the drain when they could be better used elsewhere.


The Final Attempt – the Trump “build-a-wall” approach

The last and final method has resulted in ZERO drain flies ever since its one-time application more than 2 months ago. I purchased a stainless steel and copper drain trap from Qoo10 for only $12. The trap has a check valve (a one-way valve) which allows water to flow down into the drain but nothing to come up.

Although there are many other floor drains in my flat, thankfully, the flies only seem to be coming from one of them. For the rest of the drains, I also put in a “wall” (just in case) but not a fancy one with a check valve as none of the other drains needed to have water flow down through the top. For these drains, I cut a fitted circular piece of plastic (using one of those lids from a da bao container) and stapled a string to the center of it so that I can easily lift it out.

To this day, this Qoo10 drain trap has successfully kept all flies and smells from coming into my home. The drain trap does need to be cleaned periodically, and you’ll know when it’s time to clean when the water flow is less strong. But it’s pretty low maintenance otherwise. And my home doesn’t smell like moth balls.

4 Comments on Quick, Cheap, and Non-Toxic Way to Get Rid of Drain Flies

  1. I don’t remember seeing drain flies while living in HDB flat in the last few decades. We do a few things that might have helped to eliminate the food odour:
    1) Have a cheap, simple drain strainer installed (Eg: https://www.rsvp-intl.com/wp-content/uploads/2015/11/SINK-4_nopropsv1.jpg)
    2) Don’t dump bits of food residue and waste into basin or drain (dump them into waste bin or toilet bowl);
    3) Pour some boiling hot water once a week down the kitchen basin/pipe to get rid of the stench, and to prevent oil from hardening and blocking the pipe.
    Try the above methods. Good luck!

    • Hi Abdillah, thank you for your question. The one I bought was type C with no centre hole. I also was unsure which type to buy. But I saw (from the reviews) that most people were buying type C. I’ve had the drain trap now for almost a year and it still keeps the flies out. The only thing is that it does requires cleaning (I use a toothbrush) every one to two weeks.

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