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Slow Draining Bathroom Sink Not Clogged [7 Reasons]

You have guests in your house but your bathroom sink is not draining fast.

How embarrassing would that be? This might have happened before.

But, do you know why this happens? Why do you have slow drawing bathroom sink that is not even clogged?

The reasons could be tree roots growing inside sewer pipes, issues in P-trap. Septic tank, drain and vent pipe not working correctly. Also, you may have been using chemical cleaners to clean the sink. Dumping Insoluble objects while draining and lack of maintenance also cause this problem.

Whatever the reason is, I’ve come up with doable solutions. You’ll find some hacks as well. This article will help you thoroughly in maintaining any sink drain.

Continue reading to know in detail.

What Causes Slow Draining Bathroom Sink [7 Causes]

A slow draining bathroom sink is a complete discomfort. It’s not a bathroom sink problem only. You can find a slow draining problem in your kitchen or bathtub sink as well.

If you’ve noticed, then you’ll find this problem in every house. Have you ever wondered why this slow draining happens in the first place?

There could be many reasons. Your old, uncleaned sink pipes or stoppers can be the culprit. It could be your hair strands or too foamy soaps.

You don’t need to assume anymore. I’ve noted down only seven possible reasons. These will help you understand what went wrong with your sink.

Cause 1: Stuck Tree Roots

Tree roots are mostly stuck inside the sewer line. They love the sewer line because it has all the ingredients roots need to grow. 

But, how to identify stuck tree roots that cause slow draining?

Any bad smell coming from the sink is an indicator. Gurgling sound while draining also signals tree roots growing in the pipe. 

Other than that you may see insects, like earthworms coming out from the bathroom sink. These all indicate that the tree root is growing inside the sewer line. 

When it happens, the sink finds it difficult to drain. And you get slow draining.

It’s time to check whether it’s a tree root problem or not.

Cause 2: P-Trap Issues

Next you can inspect the p-trap. The p trap is very helpful. It protects our house from sewer gas. Sewer gas stays in the curve where it already stored water. That’s how water blocks hazardous gas.

Unfortunately, the p-trap could also be a reason for slow draining. Regular dumping of hair strands, shaving foams, or other frothy soaps gets stuck inside the p-trap. It further helps other objects to create a blockage. 

If the p-trap doesn’t get enough space for passing waste, it’ll surely cause slow draining. 

You can call a plumber to confirm the reason. 

But, I’ve planned a DIY way to fix your drain. You can check it out later. For now keep reading to have a thorough knowledge of your sink problem.

Cause 3: Septic Tank

A septic tank works as a waste decomposition tank. It holds waste coming from all the sinks of your house. It’s quite evident when the septic tank is at fault. Because then all the sinks of your house will drain slowly.

The Septic tank gets full only when it gets all covered with non-decomposable waste. Or, if you showed no concern to clean the tank for several years.

A septic tank is indirectly related to the water supply in your house. A clean septic tank thereby assures you safe water. 

Since the septic tank is underground, you need to call a handyman to fix this problem.

Cause 4: Drain and Vent Pipes

Every sink has its own draining line. The Drainpipe connects with the sewer line. This pipe doesn’t have any system to detect components that should not be in the sink. As a result, it gets drained with water.

Since both the pipes connect directly, it’s not possible to dispose of the drained waste midway.

Be careful before throwing anything into running water.

If I talk about vent pipes, they are the ventilators. Its main purpose is to even out air pressure inside the drain pipe. 

Vent pipes are located outside and get all the weather. When it’s snowing, it can be covered with snow. The moment this occurs the drain pipe doesn’t get the correct air pressure. This results in slow draining.

Also, in autumn, flowers can get stuck inside vent pipes. This again causes poor ventilation.

This problem doesn’t get enough attention. An unclogged vent pipe ensures a normal draining rate at the bathroom, kitchen, and also shower drain. That’s why you should vent a shower drain or bathroom drain.

Cause 5: Use of Chemical Cleaners

We all use drain cleaners that are chemically infused. Why? Because it gives a shiny, new look to our sink, shower, or tub drain.

Cleaning with a powerful cleaner is good to maintain hygiene. But what about the chemical reactions pipes face over frequent usage?

It damages the inside of pipes and creates holes. That further causes dirty water supply into your sinks and showers. Since it decays the pipes, pipes lose efficiency and drain water slowly.

In this case, a plumber can replace your faulty ty pipe with a brand new one. But don’t ruin it again with chemical drain cleaners.

Cause 6: Other Objects

Dumping of non-compostable items into the drainer can cause a slow drain. These items include tissue papers, jewelry, and flowers, face and hair packs. 

You may have also washed your hair in the sink. Hair strands or clumps of your hair pack get caught by the drainer.

We all know what happens afterward. It’s better to keep these mentioned objects away from the sink and drainer.

Cause 7: Lack of Maintenance

Regardless of the reasons stated above, you need to do a plumbing check-up. It can be done at least once every two years. 

This will alarm you before any major incident takes place. Any of the water pipes may explode or you may get contaminated water. You wouldn’t know all these without a plumbing check-up beforehand.

Maintenance is not only necessary for the bathroom sink drain. It’s equally important for the kitchen sink, tub, and shower drain. 

Most of cases, pipes get cracked or the shower drain leaking into the basement occurs. Time to time maintenance can save you from these unwanted situations.

These are all the possible reasons I could think of. Hopefully, you’ve found your pain point.

But, what’s next? How to solve the issue?

Don’t worry! I’ve prepared solutions for you as well. Keep going!

What are the Solutions for a Slow Draining Bathroom Sink [3 Solutions]

No matter what problems you’re facing with the sink drainer, I‘ve got you. There are three must-try solutions. These will not only help you with the sink but also the tub or shower drain. 

Solution 1: Baking Soda and Hot Water

You may be confused. You and I have always heard about baking soda and vinegar formula for cleaning the drain. What we didn’t know was the chemical reaction from mixing these two.

This mixture can explode your sink with all the dirt from the pipes. Instead, use a cheaper and better solution.

You need regular baking soda mixed in hot water. Pour the mixture into the drain. Give it time to sit for 3 to 5 minutes. This will clean the drain and turn it into brand new.

Solution 2: Make Sure Stopper is Clean

Your pop-up sinks toppers must be filled with dirt. This filthy stopper needs to be cleaned. But how?

You can do it yourself. Stick around.

  • First take out the pop-up stopper. To remove this, you have to twist it counterclockwise. 
  • Grate will come up with a pop-up stopper. Then look for any hair wrapped around the grate. It’s better to use a glove while cleaning
  • After this, hold the stopper under running water and wash. You can use a used brush to scrub out dirt.
  • Once it’s all cleaned, put it back into the sink.

This is how you get yourself a clean stopper and faster water draining.

Solution 3: Use a Cleaning Tool

You may find the problem even after cleaning the stopper. Then you need to do some deep cleaning.

Remember, I talked about baking soda and hot water solution? After cleaning your drain with that, you can actually use a cleaning tool for scrubbing. 

There are various types of cleaning tools in the market. I personally prefer the versions that have a metal wire in the middle.

You can find yours from the suggestions I’m giving below:

Product 1
Product 2

After picking your tool, brush some liquid soap on the Brussels. Then take it inside the drain and scrub off all the unclean areas.

There you go, now you have a super white drain.

Got no luck? Your sink is still draining slowly. Then you need to transform into a  handyman. 

Sometimes you need to clean the p-trap. For this, I have given a DIY guideline next.

DIY Fix for a Slow Draining Bathroom Sink [P-trap Edition]

You might be getting slow draining due to a filthy p-trap. Cleaning the trap isn’t an everyday job for you. But you can easily do that within a few minutes.

Before moving into the cleaning, let’s know how to detach the p-trap. It won’t be as complex as adjusting a tub drain to a waste pipe

First, put a bucket under the sink to catch any water. Then remove the trap by unthreading. Check the inside of the trap to see if it’s dirty.

Immediately, block the sewer gas line with tissue paper. Dump any excess water that you see inside the trap.

It’s cleaning time!

You don’t need a fancy item to clean the trap. Use tissue paper. Roll it inside the trap and swirl it properly to wipe out dirt. Once the tissue comes out clean, you can set the trap back in this place.

If your p-trap is all clear and then there’s nothing to worry about. There are fewer chances of slow draining and clogged sinks. 

This cleaning isn’t feasible when you just came back from work. Wouldn’t it be better to find a way to keep all the pipes and curves clean?

If you’re looking for a permanent solution, the next section is for you.

3 Tips to Keep the Bathroom Sink Draining Normal

It’s easier than you think to keep the bathroom sink draining normal. Just replace a few habits and you’ll be good to go. 

I researched three major tips that will help everyone with the drain problem.

Tip 1: Stop Using Bar Soap

Bar soaps create more foam than liquid soaps. As you already know, foams are not welcomed down the drain pipe. This causes water flow disruption.

Using bar soap for a long time creates a stack of foams inside the drain pipe. It’s advisable to switch to liquid soaps.

Tip 2: House Water Softener

The water we normally get from a house tank is hard. That can’t dissolve the soap. 

To soften house water you need to add some chemicals into the tank. These will cause reactivity and soften your house water. Chemicals like ammonia, borax, calcium hydroxide, sodium carbonate, etc can be added.

It’s best to consult an expert before doing so.

Tip 3: Don’t Dump Hair Strands While Combing 

It’s okay to comb hair in front of the sink. Just Don’t throw hair into the sink. This blocks the water flow. And you get slow draining at first, eventually, your drain gets clogged.

The same advice applies to those who dump hair into the sink while shaving. Use  tissue paper to put all the hair and throw it in the bin. 

It’s that simple. Stop littering your sink drain.

Next time you’ll know why your sink drain is slow and what to do. Try to contact a plumber if it’s a big issue. Otherwise, follow this article to make the drain fast.  


Can you use a plunge in the bathroom sink?

Yes, you can use a plunge in the bathroom sink. A cup-style rubber plunger will help unclog any sink. To do so, fill the sink halfway with water. Cover the overflow with a plunger and plunge straight down. Doing so several times will remove the clog. The pulling motion draws the clog up.

Why is my kitchen sink draining slowly but not clogged?

It’s because the drain pipe of the kitchen sink takes all the grease, and food while draining. These get stuck inside the pipe as they don’t dissolve in water. The kitchen sink gets most of the oil and fat. It’s better to wipe all the leftovers before washing. Otherwise, you’ll get a slow-draining kitchen sink.

Will bleach help a slow drain?

No, bleach won’t help in slow draining. It doesn’t have the power to remove any scums inside the pipes. Contrary, it can create more froth inside the sink and create slow draining. You can use baking soda and hot water to clean your drain. That’ll help in faster draining.


Hopefully it’s very clear now why you have a slow draining bathroom sink but not clogged.

The reasons are easy to tackle. And you already know hacks to avoid such situations in the future.

Try using an electric drain cleaner for complete cleaning as well.

That’s all for today. Happy cleaning!