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Causes Of Smelly Floor Drains

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Have you just found out that there's a bad smell coming out of your bathroom floor drain? Well, then you’re certainly not alone!

Believe it or not, stinking drains are a pretty common problem in most households. We may not want to deal with it, but now and then, we have to brave these issues.

However, even though it's a frequent occurrence, most people don't know what causes a smelly floor drain. And, let's be honest, most of us likely forget about the existence of these outlets even when we regularly clean our bathrooms, or basements.

All this may seem like a trivial issue, but long-standing smells coming from floor drains are usually signs of plumbing problems.

It can lead to critical health issues because of the obnoxious environment created by the odour. Hence, to help you, we have come up with this guide to trace the sources of your smelly floor drains.

So, let's begin!

Causes of Smelly Floor Drains


1. Blocked Drains

This is the most obvious reason for an obnoxious smell coming out of floor drains, but it's easy to escape our minds. Many things can cause a drain to clog up, but the most common is accumulated gunk on the grate.

You may have noticed that there is a covering on top of the floor drain, which helps to hold on to the things that might clog up the pipe. It also makes it easy for the water to go down the drain.

On this grate or cover, you might find a build-up of soap scum, remnants of food, hair, dirt and other things that block the drains and cause a foul smell. However, blockages are sometimes present inside the pipe, and if you suspect that, calling a plumber might help.

2. Bacteria Or Mould Growth

When it comes to smelly drains, finding out this reason is a bit tricky. Bacteria and mould can often grow inside the walls of a drain, which may start smelling in a few days. A musty odour is usually the first hint of this issue.

This problem is particularly prevalent in bathrooms where there's frequent use of hot water. Additionally, it's also seen in places where the water may stand for a while before draining out. Also, the growth of bacteria or mould can suggest the presence of a blockage in the drain.

You should take care of this issue as early as possible to avoid prolonged exposure to the bacteria or mould, as it may lead to health problems.

drain with mould growth

3. Old Pipes

Do you still have old plumbing lines at your house? Old metal pipes that are often exposed to moisture may get rusted. This leads to cracks or holes, which may let sewage enter the drain pipe. Even when the situation isn't adverse, the smell of sewage can still seep through the cracks.

Tree roots are a common problem that may damage pipes. Hence, if there's damage to the pipes somehow, foul odours can easily reach you through the drains. In such cases, the only way to put an end to this problem is by changing or repairing the pipes with more weather or damage resistant options.

4. Drain Flies

It might be hard to believe that one of the foremost reasons for smelly drains might be flies. However, drain flies, also known as sink flies, will easily make you believe in their ability to spread foul odour.

These flies are often attracted to decomposing organic matter, which is commonly found in floor drains. These flies usually infest places during summer, as the hot and humid situation is perfect for their breeding.

You might be able to spot a few flies near the floor drain. However, in most cases, the first sign of these flies are the wriggling black larvae present near the drain hole.

It's tempting to wash the flies or larvae with water, but don't do that, as moisture helps the flies to thrive. Instead, using apple cider vinegar might get rid of the pesky creatures better.

drain flies

Ways To Get Rid Of Smelly Floor Drains

Now that you know about what causes odour in floor drains, it's time to find ways to defeat it. Most of these options will be pretty easy, and can be done with things readily available at your home. However, if you find that the smell isn't going away, seek the help of a plumber right away.

1. Pour Hot Water Down The Drain

The hot water method is a favourite technique to get rid of clogs in a drain. This trick works for both sink and floor drains. All you need to do is to pour hot or warm water down the drain. Make sure to remove any drain cap or grate beforehand.

But, if you have PVC pipes at home, we recommend using warm water to avoid melting the plastic pipes or joints. It's a useful method, as the temperature of the water can melt organic materials to unclog the drain.

As you aren't using anything toxic, the pipes won’t get damaged. For doing this method, a trick is to use the leftover boiled water from your kitchen.

2. Pour Hot Vinegar Down The Drain

As we mentioned before, pouring warm vinegar down the drain can also be a good solution, as vinegar is excellent for removing bacterial growths and mould. Also, the warmth of the hot vinegar will melt down the organic materials blocking the drain.

To start, you will need to warm the vinegar on your stove or in the microwave. Wait for it to get a little steamy, and then prepare to pour it down the drain in a way that the vinegar touches the walls of the drain pipe.

Follow it up by taking a plunger and pushing it on the mouth of your floor drain as you would do to a toilet. This takes away any further clogs left in the drain pipe. You can repeat this step every month to avoid smelly drains.

warm vinegar in drain

3. Baking Soda And Hot Water Treatment

The internet is obsessed with baking soda, and we admit that so are we. It's a miraculous and eco-friendly cleaning agent that works for our bodies as well as for the drains. You can use this treatment as a monthly routine to get odour-free floor drains.

To do this, you will need baking soda and hot water. You can also take white or apple cider vinegar for the last step, but it isn't necessary.

So, start by pouring a cup of 100 gm of baking soda down the drain. Wait for 15 minutes, and follow it up with the hot water. After waiting for another 15-20 minutes, pour an additional 100 gm of baking soda into the drain, followed by either hot water or vinegar.

This treatment will give good results and eliminate the foul smell from your floor drains.

What Can You Do If The Smell Persists?

Unfortunately, in some cases, the smell will refuse to go away. In such a situation, it's best to take help from a professional. Many people resort to using bleach or commercial drain cleaners, but it's better to get an expert's opinion.

Only a licensed plumber will be able to help you with the problems of smelly floor drains. And you should ensure a thorough check-up of the drainage and plumbing system of your house to prevent and avoid further blocked drain problems.

Getting Rid Of Your Smelly Floor Drain

That's all we had to tell you about smelly floor drains. We have tried to give you a comprehensive idea about the reasons that might cause the problem and attempted to provide some easy solutions.

Remember to regularly clean the drain grate to keep it clear of the usual gunk that might end up blocking the pipe. Also, keep pouring hot water once a week or try to do the baking soda and hot water treatment every month.

And, if the smell seems to persist even after regular cleaning and maintenance, seek help as there might be further problems in the plumbing system of your house.

With that, we have come to the end of this informative guide. Do let us know if you have any more queries regarding smelly floor drains or other household plumbing issues.

Till then, bye and take care!

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