Is That Rotten Eggs? Why Does My Drain Smell?

drains smell like rotten eggs

Maintain Drains plumber jetting an external drainRotten eggs are an unpleasant smell – one you definitely don’t want in your home. You can spend days trying to find the cause – is it the bin? The fridge? Or the dog? Often, it is actually the sink in the kitchen or the drain in the garden which is causing these unpleasant odours – and the smell of rotten eggs could be a sign of a more serious issue – even a dangerous one. Read on to find out. 

Smelly drains are a common problem. Sometimes, it’s caused by a build-up of food and dirt, however, sometimes it can be a sign of a bigger issue. Understanding the cause of the smell and how to get rid of it is important to get your drains smelling fresh and flowing freely again – and keep your home safe from gases that could be hazardous to your health. 

The Cause of a Smelly Drain or Sink

There are several likely causes of your drain odours. The first thing to look at is where your drain is located and how it is used. For example, if it’s your kitchen sink, the smell is likely caused by a build-up of food. If it’s the shower drain, it could be a build up of dirt and hair. 

It isn’t a fun job, but discovering the cause of the smell can help to treat it and prevent it in the future. There are four common causes of smelly drains or sinks:

1. Trapped Food Blockages

While you may take precautions to prevent food in your sink, small pieces and other organic matter can still get in your drains and cause a bad odour. This blockage can stop the flow of drains completely or cause them to drain slower than normal.

2. Clogs and Bacteria Build-Up

A common cause of a bad smell is simply bacteria. This usually occurs in indoor bathroom drains and sinks, as bacteria can come from hair, dirt or products that have gone into the drain. There are ways to prevent this build-up including bathroom drain traps. It is best to receive advice from a plumber to find the best prevention for you.

3. Pipework and Plumbing Errors

If you’ve had work done recently and notice a new smell, it could be due to a plumbing error. This could be a missing trap or vent, or even a leaky pipe. It could be worth contacting the plumbing company again or asking a second company to assess the smell and investigate the cause.

4. Collapsed Drain

Finally, if you notice a lingering odour that persists after you have had your drains unblocked, it may be a sign of a collapsed drain. This can happen after years of poor drain maintenance or damages and cracks in your pipes. Along with a bad smell, you may also notice damp or mould throughout the property and a sunken or wet area in your garden. You must contact a drainage expert if you think your drain has collapsed.

Why Does it Smell Like Rotten Eggs – And Why Is That Dangerous?

Maintain drains plumber unblocking an internal drain in a kitchenMost people describe bad smells from drains as being like the smell of rotten eggs. They aren’t pleasant, but there is a scientific reason for this. This smell often comes from a gas known as hydrogen sulfide, which is formed when bacteria grows in sewage, drains or the ground. 

If you don’t use the drain or sink often, the hydrogen sulfide could come directly from the sewer itself. When water in the p-trap dries up, the gas can rise from the drain. 

It’s important to know that hydrogen sulfide gas can be hazardous to human health. As a toxic gas, it can be about as dangerous as carbon monoxide. That’s why we recommend consulting an expert if this smell is coming from your drains. 

Other Common Drain Smells and Odours

Hydrogen sulfide is very pungent and can be likened to many unpleasant smells. Some property owners have reported drains smelling like garlic, rotten vegetables or sewage. 

It’s simple: healthy drains don’t smell. So whatever your drains smell like, it probably isn’t a good sign. Contacting a professional should be the first step to understanding the smell and getting it out of your property.

Outdoor and Indoor Drain Smells

While indoor drain smells can be easier to identify, outdoor drains are much more complex. There can be many more causes of outside drain smells and they often link to problems deep within the drainage system. It could be an outdoor drain blockage, or it could be something bigger such as a collapsed drain or damaged pipework. 

If you notice a smell coming from a drain outside your home get in touch with Maintain Drains. Our friendly team can investigate the issue and give you a breakdown of the cause. Our team then works on a case-by-case basis to resolve the problem and get your drains flowing back to normal as quickly as possible with no more nasty smells.

How to get rid of Drain Smells and Neutralise Odours

Often, when noticing an unpleasant smell, the first thought is “how do I get rid of it?”, especially if it smells of rotten eggs. While odours can be masked with products such as Mr Muscle or Jeyes Fluid, if the root cause of the problem is still there, the smell will return. 

The best way to remove drain odours is to go directly to the cause of the smell – whether that’s a food build-up or damaged pipes. By contacting a professional plumber, you can get straight to the cause of the issue and have unpleasant odours removed completely.

How to Prevent Smelly Drains

We always recommend putting measures in place to prevent issues before they arise. While drain odours have many causes, preventing them is actually quite simple and can be done through regular maintenance. Ensuring drains are clean, with minimal build-up, and they are used properly is important. Prevention is also important and there should be measures implemented to ward off nasty smells. 

Life is busy, and it’s easy to forget to maintain your drains. Regular pre-planned maintenance can do the work for you and means a drainage expert can nip any problems in the bud before they arise. As well as time, it can also save you money, as prevention measures are more affordable than last-minute emergency repairs. This service is ideal for both homes and businesses. To discuss planned maintenance of your drains, give us a call today.

Drain Smell Cleaners

There are many products on the market which claim to clean your drains and stop nasty odours. While some are good, others are cheap and don’t actually work. Many drain cleaning products are made with toxic chemicals, and can actually cause more damage than repair. 

Chemical drain cleaners are often a short-term fix and will not resolve the cause of the smell. Whether it’s a bacteria build up or a plumbing error, it isn’t likely that a cheap drain cleaner will repair it. Most drain problems need intervention and repair by a professional who can tackle the issue and prevent it from recurring. 

When to get Help From a Professional

Maintain Drains plumber with children and dog

A smelly drain could be dangerous to your health, so it is recommended to contact a professional as soon as the smell is noticed. It isn’t pleasant, and getting it resolved as soon as possible will ensure your home is safe and smells clean. 

In the meantime, you can use odour masks such as air fresheners to reduce odours. When contacting a drainage expert, they should advise you on how to reduce the smell and deal with the issue.

You can contact Maintain Drains 24 hours a day, 7 days a week for all drainage issues. We specialise in blocked drains and pride ourselves on our 5-star service in and around Dorset. Request a callback from our team today to receive a free quote. Our team of experts can advise you on the best solution which works for you and your drains.


Q: What are the common causes of smelly drains or sinks?

A: The common causes of smelly drains or sinks are trapped food blockages, clogs and bacteria build-up, pipework and plumbing errors, and collapsed drains.

Q: Why do drains sometimes smell like rotten eggs?

A: Drains may smell like rotten eggs due to the presence of hydrogen sulfide gas, which is formed when bacteria grows in sewage, drains, or the ground.

Q: Is hydrogen sulfide gas hazardous to human health?

A: Yes, hydrogen sulfide gas can be hazardous to human health, similar to carbon monoxide. It’s important to consult an expert if this smell is coming from your drains.

Q: How can I get rid of drain smells and neutralise odors?

A: The best way to remove drain odors is to identify and address the root cause of the smell, whether it’s a food build-up or damaged pipes. Contacting a professional plumber is recommended for a thorough solution.

Q: How can I prevent smelly drains?

A: Regular maintenance is key to preventing smelly drains. Ensuring drains are clean, with minimal build-up, and used properly can help ward off nasty smells. Planned maintenance can save time and money by addressing issues before they become major problems.

Q: Are chemical drain cleaners effective in removing drain smells?

A: Chemical drain cleaners may offer a short-term fix, but they may not resolve the root cause of the smell and can potentially cause more damage. For a thorough and lasting solution, it’s best to seek professional intervention and repair.

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