How to clean sink overflow / 7 best free cleaning tips in 2023
Have you ever seen that hole at the back of your sink and wondered what its purpose was? Was it just there for decoration? It didn’t seem likely, but you just didn’t know what it was for. And then one day, for whatever reason, your sink’s drain got blocked and the water started rising…and rising…and rising. And you didn’t know what to do! Maybe the handle broke off and you weren’t able to turn the water off. In this article, we will tell you how to clean sink overflow.
The standard waste-overflow system is a small opening located at the top of the sink. Thanks to it, water is drained if the pressure is too large or the tap is not turned off. That is, when the water rises above the set level, then it goes through the overflow hole into the drain, and not onto the flooring.

What is drain-overflow system?
Such a system was invented in Western Europe and is especially common in England, where they use water very sparingly and wash from a bowl with a closed drain, which increases the risk of flooding. When the water level rises above the maximum mark, the water flows through the overflow hole to the drain, and not to the floor. In our country, it is customary to wash under the jet, the need for “drain-overflow” arises less often, but most sinks are still equipped with a “drain-overflow” system. This is not an additional option, but an integral part of the design of the sink: either it is there or it is not.
What to do with sink overflow hole?
Whatever the case, you watched the water rise–and then stop rising. What happened? Well, that little hole we just talked about did its duty and saved your bathroom from being flooded. Instead of the water spilling all over the sink, it went down the hole and into your sink overflow.
Now, you need to make sure that this overflow hole doesn’t become clogged. Why? Well…do you want water to actually flood your bathroom next time? We didn’t think so! We get that cleaning out your sink’s overflow is probably super low down on the list of things you want to do with your life–but it is necessary. So the next time you have a spare minute, roll up your sleeves, pull on some gloves, and prepare to get down and dirty in order to spare yourself from flooding later on. Unsure just how to go about cleaning the overflow hole?
6 tips on how to clean sink overflow and the drain
Tip #1: Gather your tools
We’ve already mentioned gloves, so make sure you have some on! You also may want to consider wearing a mask to help block any bad smells or fumes that may come out of the sink overflow hole (this isn’t as important as gloves though, since you’re not cleaning a toilet). You’ll also want to have a brush on hand–not a hairbrush, but the sink-cleaning kind!
If you don’t have one readily available and you don’t feel like going to the store, a pipe cleaner will do in a pinch. You may want to wrap it around a pencil or a zip-tie in order to have more firmness when digging gunk out (just be gentle, especially with the pencil, as you don’t want to damage anything).

Tip #2: Dig the gunk out
A good tip on how to clean the sink overflow is to dig the gunk out. Okay, this part will probably seriously gross you out–but just grit your teeth and keep going. Insert the brush (or pipe cleaner) into the sink overflow hole and pull it in and out several times in order to loosen up the gunk and keep the whole thing from clogging. You may have to rinse off the tool you’re using between each use, depending on how much you end up digging out of the overflow.
Tip #3: Add boiling water
This is the most common method that helps restore water drain and unclog pipes. To overcome contamination, you will need to prepare a heated or boiling water in advance. Then one and a half liters of hot water is poured into the overflow and the procedure is repeated after half an hour.
People who have plastic pipes installed should not use boiling water. Therefore, ordinary warm water is poured into the pipes, heated to 50-65 degrees.
Tip #4: Use baking soda and vinegar to get rid of smells in sink overflow hole
To implement this method, you need the following ingredients:
- soda
- vinegar (it is best to use white distilled)
- boiling water
- rag or terry cloth
Cleaning sequence:
Pour half of the soda bag into the sink overflow hole. It is important that the baking soda is dry.
Pour vinegar in a volume – 0.5 tbsp. It’s good if you warm it up a little.
Cover the hole immediately with a rag. This will keep the foam that forms from the baking soda and vinegar inside the pipe.
Leave everything as it is for 30 minutes. During this time, the debris that blocked the outflow of water will dissolve.
Boil the kettle afterwards. As soon as the allotted time is up, pour hot or boiling water into the small hole.
The resulting caustic foam effectively corrodes all kinds of blockages, eliminating dirt and odor. If it was not possible to get rid of the blockage immediately, repeat the above steps. The foam will do the work. Try the same procedure on your sink drains.

Tip #5: Use enzyme cleaners to cut through the foul odor
Do you know what causes most (if not all) of the smell in your sink’s overflow hole? Bacteria. And with a good enzyme cleaner, you’ll be able to get that bacteria cleaned out in an efficient manner! Simply add the recommended ‘dose’ of enzyme cleaner into your overflow, let it soak in overnight, and then run some warm water through as well. Goodbye dirt, goodbye smell!
Tip #6: Use sink overflow cleaning foam
Do you want it to be quick and easy this time? Are you not the type for grandma’s cleaning products? Then make a bathroom & kitchen update and use the cleaning foam from the supermarket. By the way, you can also clean your drain (foaming drain cleaners) and pipes with the foam.
Tip #7: Contact a plumber if needed
If you’ve tried all of the above tips and your overflow hole is still blocked and foul-smelling, you need to contact a good plumber. You could also call one if you just don’t want to bother with the overflow hole yourself. Chances are that the above tips will work, but if they don’t it could be the sign of a more serious problem. That could have serious repercussions for other areas of your home’s plumbing. Better to be safe than sorry, so call a plumber!
Conclusion
The overflow system is widely used in bathrooms, but it was only introduced to sinks much later. Meanwhile, such a sink drain prevents water from leaking out of the container when it gets clogged, this is a very important function, thanks to which a lot of troubles are prevented. But in order for the system to work correctly and reliably, you should take a responsible attitude to the selection of products and carry out the installation in accordance with the technology.
You can also modify the above tips and clean the drains or garbage disposal in your kitchen sink using the same tools.
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