You come home to your lovely home and it reeks? If it’s coming from the drain, the stink in your nostrils is probably hydrogen sulphide produced when bacteria feeds on the gunk clogging your pipes—a clogged drain is a common cause of these odors.
A smelly bathroom or smelly sink is often caused by similar issues in the drains, with unpleasant odours originating from kitchen or bathroom sinks due to buildup or blockages.
And apart from stinking up a storm, those smelly drains can give you a headache, make you feel weak, irritate your eyes and upset your stomach.
Are Smelly Drains Bad for Your Health?
Smelly drains aren’t just gross – odours like sewer gas smell and musty odour can also be a sign of hidden health risks. Gases like hydrogen sulphide and methane can cause dizziness, nausea and prolonged fatigue if left unchecked. If you or your family experience symptoms when at home, take it seriously and deal with the source of the smell asap, as persistent odours may indicate underlying plumbing issues that require attention.
Why Do Drains Smell in Australian Homes?
Your smelly drains may be caused by:
- Rotting food
- Food buildup and food debris in kitchen drain or bathroom sinks
- Mould growth (especially in damp climates)
- Sewer or venting problems
- Leaks, corrosion or other plumbing damage
- Drain flies or pests
- Tree roots in underground pipes
A blocked drain in the kitchen drain or bathroom sinks can quickly lead to unpleasant odors.
Because Australia’s warmer weather speeds up bacterial growth, smells tend to be stronger in summer. An unused bathroom sink or an outdoor drain can dry out quickly leaving gases to enter your home.
Identifying the Source of Smelly Drains
Before you can clean smelly drains effectively, it’s important to track down exactly where that bad smell is coming from. Start by giving your kitchen sink drain, bathroom sink, and shower drains a quick inspection. Look for any obvious signs of food particles, soap scum, or other debris that might be stuck in the sink drain or around the drain cover.
Don’t forget to check the p trap—the curved section of pipe under your sink. If it’s dry or clogged with gunk, it can let sewer gas and other unpleasant odors escape right into your home. A quick way to check is to shine a torch down the drain and see if there’s standing water in the p trap. If not, that could be your culprit.
If you notice slow draining or suspect a blockage, use a drain snake to clear out any buildup in the drain pipes. Sometimes, the source of a smelly drain is deeper in the plumbing system, especially if you’ve tried cleaning and the smell lingers. In that case, it’s best to call a professional plumber to inspect your drains and make sure there aren’t any hidden issues causing those stinky drain smells.
How to Stop a Smelly Drain (DIY Fixes)
If your drains stink, you need to restore peace and health to your home asap – and you might even get away with not calling your friendly local Sydney plumber! Before cleaning drains, always wear rubber gloves to protect your hands from dirt and harsh chemicals. Cleaning smelly drains is an important DIY maintenance task, and the vinegar method is a popular and effective way to eliminate odors. Here are a few tricks:
1. Baking Soda
You already know that baking soda (also known as bicarb soda) and vinegar is great for fizzing up a storm and unclogging your sink or bath drain. The chemical reactions also neutralise bad smells:
- Pour the baking soda (or bicarb soda) down the drain
- Slowly pour hot vinegar into the drain after the baking soda to maximize cleaning power
- Plug the drain for 15 minutes
- Pour boiling water slowly down the drain to flush away debris and bacteria
Note: Always pour the liquids slowly to avoid splashing and to ensure they work effectively in the drain.
2. P-Trap Re-fill
A dry p trap is one of the most common reasons for smelly drains, especially in sinks or showers that don’t get used often. The p trap is designed to hold a small amount of water, which acts as a barrier to stop sewer gases from wafting up into your home. If you notice a foul smell coming from a drain, simply pour hot water down the drain to refill the p trap and restore that protective seal.
To prevent smelly drains, make it a habit to run hot water through all your drains—especially in guest bathrooms or laundry sinks that might sit unused for weeks at a time. This simple step helps keep your plumbing system healthy and keeps sewer gases where they belong: out of your living space.
3. Bleach Wash
Another deodoriser is bleach. Fill the sink, add a cup of bleach and carefully let it drain. This method deodorises and loosens organic matter. If bleach is ineffective, you can try a commercial drain cleaner, but use caution to avoid pipe damage, especially with older or PVC pipes. Another option is mineral oil – though it will suppress odours but won’t break down clogs like bleach does.
Step-by-Step: How to Clean a Smelly Drain
For stubborn smells try this:
- Boil a kettle and pour it down the drain.
- Add half a cup of baking soda.
- Pour in one cup of white vinegar.
- Cover and let it work for 15-20 minutes.
- Flush with near-boiling water.
If you have any leftover hot water, use it to flush the drain again to help remove any remaining debris or buildup. Afterward, run cold water down the drain to help solidify and move any remaining gunk, keeping your drain clean and odor-free.
Repeat as needed or move on to another method if the smell lingers.
Natural Ways to Deodorise Your Drain
If you prefer eco-friendly options:
- Lemon and salt for a fresh scent in kitchen sinks.
- Vinegar ice cubes in the garbage disposal.
- A few drops of eucalyptus or tea tree oil with hot water for natural deodorising.
- Use a drain cover or strainer to catch food particles and prevent them from entering the drain.
These are safe for most plumbing systems and great alternatives to harsh chemicals.
Smelly Drains in the Kitchen, Bathroom and Laundry
Different drains smell for different reasons:
- Kitchen: A smelly kitchen sink drain is often caused by food debris, grease, and soap buildup. Prevent odors by using strainers and hot water flushes to keep the drain clear.
- Bathroom: Smelly bathroom drains and the shower drain are common sources of foul odors, often due to hair, soap scum, and bacteria buildup. Clean hair catchers regularly and try enzymatic cleaners to address these issues.
- Laundry: If your laundry drain is draining slowly, it can indicate buildup of lint, detergent sludge, or standing water, which may lead to stinky drains. Monthly hot water flushes can help prevent these problems.
Smelly sink drains are a common household issue, but regular cleaning and maintenance can effectively resolve most odors.
Plumbing Traps and Vents
The P-trap or S-trap in your plumbing holds a small water barrier to stop gases from entering your home. If this dries out, smells will escape. Vents are designed to push gases outside. Blocked vents (from dirt, debris or bird nests) often cause drains to smell indoors.
Plumbing problems such as sewer line problems can also allow sewer smell to enter your home if not addressed.
Smelly Drains Caused by Pests
Sometimes, the source of a smelly drain isn’t just old food or soap scum—it’s pests. Rodents, insects, and especially drain flies can find their way into your drain pipes, leaving behind unpleasant odors and even health risks. To keep pests out and prevent smelly drains, regular cleaning is key.
Try using a cup of baking soda followed by half a cup of white vinegar to create a natural chemical reaction that helps break down debris and discourage pests from settling in. Pour the mixture down the drain, let it fizz for a few hours, then rinse with hot water. This not only helps eliminate bad smells but also keeps your drain pipes clear of buildup that attracts pests.
For extra protection, install a drain cover or screen to block insects and other critters from entering your drains. If you notice signs of a pest infestation or the smell just won’t go away, don’t hesitate to call a professional plumber. Regular maintenance and a little baking soda and vinegar can go a long way in keeping your plumbing system fresh and pest-free.
Smelly Drains Caused by Pests
Sometimes the smell isn’t from waste at all. Drain flies thrive in the slimy gunk coating pipes and produce a rotten smell. Cockroaches can also crawl in through cracked drain covers. If you’ve identified pests, clean the pipe thoroughly and consider calling a pest controller.
Why Drains Smell Worse in Summer
Summer in Australia is notorious for making drain odours worse. Musty odour can also become more noticeable in summer due to increased humidity and mould growth. Warm weather accelerates bacterial growth and evaporates water in traps especially in unused bathrooms or outdoor drains. Prevent foul summer smells by running water through every drain at least once a week.
Smelly Drain Prevention Checklist
The best way to deal with smelly drains is to prevent them altogether. Every month or so:
- Run boiling water down drains.
- Use a preventative baking soda and vinegar flush.
- Clean garbage disposal units.
- Don’t put fats, oils and chunky scraps down sinks.
- Check unused drains so P-traps don’t dry out.
- Schedule a professional drain inspection annually.
- If odors persist despite regular maintenance, schedule a professional drain cleaning service for a proper clean to ensure thorough removal of stubborn smells and prevent future issues.
Quick Fixes vs Long-Term Drain Solutions
Quick fixes like bleach or a vinegar flush will mask odours but may not restore your pipes condition. For long-term freshness:
- Use enzyme-based cleaners safe for regular use.
- Upgrade to eco-friendly commercial products.
- Have deep clogs professionally cleared.
- Repair or replace pipes that are damaged or corroded.
- Call professional plumbers to clear a blocked drain quickly and prevent recurring issues.
When to Call a Plumber
If DIY efforts don’t get rid of the smell it could be a sign of a deeper plumbing issue. Call a licensed plumber if:
- Smells linger no matter what you do
- You have a persistent smelly drain problem or drain smell
- Odours are in multiple drains
- Pipes are gurgling or sinks are emptying slowly
- Leaks or corrosion are visible
Your drain might already be clogged or there could be a bigger problem in your sewer line.
Note: When attempting DIY fixes, take special care with PVC pipes. Certain chemicals and hot water can damage them, so always follow recommended cleaning methods.
We Know How to Stop Drains from Smelling
If that sounds like it might be the case at your place or you just want a professional to deodorise your smelly drains, the friendly and fully licensed team at Rapid Service Plumbing will be happy to help. We offer a professional drain cleaning service to resolve any smelly drain problem quickly and effectively.
We are the 24-hour emergency plumber service Sydney trusts. So to remove that plug from your nose and sort out your smelly drains and more, call Rapid Service Plumbing now.
