Why does my bathroom smell like sewer stench when I’ve only just cleaned it? It’s one of the most frustrating (and gross) questions a homeowner even needs to contemplate – but it’s actually one of the most common reasons people call us for sewer system-related issues. That disgusting, gut-wrenching rotten-egg smell that we all know too well has a very bad habit of hanging around – no matter how much bleach you throw at it.
But don’t worry. There’s some good news (as you pinch your nostrils to hide the stench).
In reality, the cause is usually fairly simple to find – as almost as simple to fix. The key is knowing where to look.
In our blog today, we’re going to talk about what’s really going on in your stinky sewer pipes – and what you can do about it with not a lot of fuss.
How sewer smells get into your bathroom
To fully understand the source of that disgusting smell, you’ll have to know a little more about how your plumbing is designed to keep it out of your nostrils in the first place:
- Every drain in your bathroom has a U-shaped bend underneath called a trap
- It holds a small pool of water
- That water acts as a seal, blocking sewer gas from rising up through the pipes and into the room
- Your plumbing also has vent pipes running up through the roof, which let gas escape outside and keep the water in those traps where it belongs.
Does that help at all?
After all, most of you are basically asking the same thing: Why does my bathroom smell like a sewer when it looks perfectly clean? And in nearly every case, something has clearly broken that seal or blocked the escape route. Hence the stench.
7 Causes & how to fix them
So, why does it smell like sewer in my bathroom?
The good news is that in most cases, it’s really all about these most likely 7 causes:
1. A dried-out trap
If a shower or floor drain hasn’t been used for a while, the water in its trap can evaporate.
That leaves a totally open path for horrible sewer gas to escape … into your nostrils, and into your house.
Spare bathrooms and floor wastes are the most common suspects we come across – and it only gets worse in hot weather.
THE FIX:
- Run water down every drain for a minute or so
- Pour a bucket of water into floor wastes every couple of weeks.
2. Gunk building up in the drain
Over enough time, it’s just inevitable that all that hair and soap scum that goes down there will build up inside your shower and basin drains. And as that gross sludge breaks down, it starts to smell – a lot – like disgusting, raw sewage.
THE FIX:
- Remove the drain cover
- Clean out what you can reach.
If the smell keeps coming back, a plumber can clear the drain properly with a high-pressure water jetter.
3. A dirty basin overflow
You know that little hole near the top of your basin? It does a helpful job, but it also collects grime and stale water over time. After all, it’s so easy to forget that it’s even there!
THE FIX:
- Clean inside the overflow
- Use a small bottle brush
- Flush it through with hot water.
4. A faulty toilet seal
Toilet smell like sewage – even right after you’ve cleaned it? The likely cause is the seal. And that would be exactly where the pan meets the sewer pipe.
A worn seal, or one that has shifted over time, allows horrible gas to escape around the base of the toilet. And making it even worse is if your toilet is loose just a tiny bit.
THE FIX:
A plumber can replace the seal, and refit the toilet so it sits firmly in place.
5. A blocked vent pipe
An accumulation of leaves, or even bird nests, can simply block the vent pipe on your roof.
When it happens, the pipes will be sucking the water out of your traps, producing the horrible stench.
To spot it, you’ll often hear gurgling when a toilet is flushed, or when a basin is draining.
THE FIX:
You need a licensed plumber, not only because properly clearing a roof vent means working at dangerous height.
6. A cracked or damaged pipe
It’s the classic head-scratcher – Why does my bathroom smell like sewer but there’s no leak anywhere you can see?
Maybe you can’t see it, but there’s probably a cracked pipe hidden inside a wall or beneath the slab. That way, sewer gas can happily escape without a single drop of water showing.
But your nose definitely senses it!
THE FIX:
A CCTV drain camera can pinpoint the damage – and many cracked pipes can be repaired with non-invasive, no-dig pipe relining.
7. A blocked sewer line
If your main sewer line has started to block, waste and gas can back up into your lowest fixtures – and they’re usually the ones in the bathroom.
Slow drains in several places at once are a strong warning sign.
THE FIX:
A plumber will locate the blockage with a CCTV drain inspection camera, and then clear it quite easily with the incredible power of ultra high-pressure water jetting.
When the smell comes and goes
You might sniff it here and there, but if the smell doesn’t stick around constantly, that can make it so much harder to pin down. You might therefore be asking:
Why does my bathroom sometimes smell like sewer and other times smell completely fine?
Well, intermittent smells like that quite often point to:
- A trap that has just dried out in hot weather
- A partly blocked vent that only causes trouble when several fixtures run at once
- A windy day that can push and pull air through a damaged vent.
What that means for you? Take careful note of when exactly the smell is occurring – because it will give your licensed plumber a very useful clue.
When the water itself smells
But just sometimes, there’s the even more worrying version of the question:
Why does my bathroom water smell like sewer when it comes straight out of the tap?
It’s a very valid question, because what you put down your throat really does need to be clean, healthy – and not smelling of sewerage!:
- Run the hot tap and the cold tap separately
- Give each a sniff.
If it’s only the hot water than smells off, the cause is probably inside your hot water system – where a reaction between the water and the tank’s anode can produce a rotten-egg smell.
In that case, you’ll need to ask your plumber about how to resolve that – whether it’s a replacement anode rod or a flush, or possibly even a new hot water system entirely.
But if the cold water smells too, contact your water supplier. Who’s that?
- Urban Utilities in Brisbane
- Unitywater on the Sunshine Coast and in Moreton Bay.
When should you call a plumber?
While some not-so-foul smells can be sorted at home, others definitely need professional help – and you need it fast.
Call a plumber ASAP if:
- The smell comes back after you’ve cleaned the drains
- You hear gurgling from toilets or drains
- Several drains are draining slowly
- There’s dampness or staining around the base of the toilet
- Water is backing up into the shower or basin.
Get rid of that sewer smell for good
The team at Static Plumbing uses CCTV drain cameras and high-pressure jetters – and more – to track down the source of sewer smells across Brisbane and the Sunshine Coast. We can repair damaged pipes with no-dig pipe relining and other fast, affordable, cutting-edge methods.
You’ll always get an upfront price before any work begins, and a 12-month workmanship warranty – extended to lifetime warranty for Static Members.
So, reach out to our hard-working Brisbane or Sunshine Coast teams today – and you can also book online.
