The simple washing‑up bowl trick that stops drains smelling for weeks, without chemicals or plumbers

Thomas Wilkins • December 10, 2025 16:25

Sunday night, pasta pans stacked in the sink, and there it is again: that sour, drain‑breath whiff that hits you as you pull the plug. You run the tap, slosh in a bit of leftover washing‑up liquid, maybe even glug some bleach down there “just this once”. By the next evening, it’s back.

I ended up on my knees under the sink one miserable Tuesday, sniffing around the U‑bend like a confused bloodhound, convinced something had actually died in there. The plumber I rang was very calm and very expensive. “Probably just a build‑up in the trap,” he said. “We can jet it.” The quote made my eyes water more than the smell.

Two weeks later, an older neighbour showed me a trick involving nothing but a washing‑up bowl and hot water. No caustic gels, no dismantling pipes, no mysterious powders that fizz and do absolutely nothing. I tried it that night. The smell vanished and didn’t come back for weeks.

Here’s what’s going on in your drain – and exactly how to use that bowl to reset it.

What’s actually making your drain smell

We like to pretend the plughole is a magic portal where things disappear. It’s really a short slide into a warm, sticky holding pen called a trap.

Under almost every kitchen sink is a U‑shaped or bottle‑shaped bend in the pipe. That bit always holds some water; it works as a barrier to stop sewer gases drifting back into your kitchen. Over time, though, a few things start to collect there:

Fine bits of food you didn’t scrape off properly
Fats and oils that cooled and stuck to the pipe
Soap scum and general kitchen grime
Bacteria happily living on all of the above

That mix clings to the inside of the pipes as a thin, slimy layer called biofilm. It doesn’t look dramatic, but it stinks. Every time you drain a sink of lukewarm washing‑up water, a little more residue settles in. The water sitting in the bend takes on the smell, and up it wafts every time the plughole opens.

Bleach and harsh drain cleaners promise miracles, but they often just bleach the top layer of slime and then slide past, barely touching the sides. You’re lighter by £5, the smell is slightly perfumed for a day, and the problem is still there.

The washing‑up bowl trick, step by step

This is the move: you’re going to turn your washing‑up bowl into a mini water tank that sends a powerful column of hot water through the pipe in one go, scrubbing out the trap and the first stretch of waste pipe.

You need:

Your ordinary washing‑up bowl
The hottest tap water you can get (optionally topped up with a kettle)
A working plug for the sink

Do this when the sink is empty and relatively clean.

Check the plughole.
Lift out any built‑in strainer and remove visible bits of food or debris with a bit of kitchen roll. You don’t want to simply ram a big lump further down.
Seal the sink.
Put the plug in properly so the sink will hold water. If your plug is a bit leaky, press it down firmly or twist it to seat it well.
Fill the washing‑up bowl with very hot water.
- Run the hot tap until it’s at its hottest, then fill the bowl right to the brim.
- If your hot water isn’t that hot, carefully top it up with a kettle so it’s hot but not violently boiling. (Straight‑off‑the‑boil water can be harsh on some plastic fittings; let it sit for 30 seconds.)
Set up the “flush”.
Stand the full bowl in the empty, plugged sink. Position yourself so you can lift the bowl with one hand and pull the plug with the other.
Release it all at once.
In one smooth movement, pull the plug and immediately pour the entire bowl of hot water straight down the plughole in a steady gush.
- The idea is to send a solid column of hot water charging through the U‑bend and along the horizontal pipe, not a gentle trickle.
- You might hear a short, satisfying glug as trapped air, scum and stale water are shoved through.
Repeat 2–3 times.
Refill the bowl and do the same again once or twice. By the second or third round, the water should be running away faster and any musty smell usually disappears.

It takes about five minutes. No tools, no chemicals, no dismantling pipework. Just using gravity and a washing‑up bowl to do what it was secretly built for.

Why this works better than “just running the tap”

Think of the difference between a toilet flush and a dripping cistern. One actually shifts things; the other just adds to the mess.

A thin stream from the tap barely disturbs the gunk clinging to your pipes. Most of it hugs the top layer of water and snakes through the middle of the pipe, leaving the greasy ring around the edge untouched. The smell lives in that ring.

By sealing the sink and then releasing a full bowl of hot water in one go, you:

Create pressure. A deep slug of water pushes through the bend and along the pipe with force, scrubbing more of the biofilm off.
Heat up the grease. The sustained hot temperature softens fats that have clung on, helping them break away.
Replace stale water in the trap. The old, smelly water sitting in the U‑bend gets entirely swapped out for fresh.

Because you’re not relying on chemicals, it’s:

Safe for septic tanks and older pipework
Kinder to pets and children (no corrosive liquids under the sink)
Cheaper than constant bottles of branded unblocker

You’re not solving a one‑off “blockage”; you’re doing a mini deep‑clean of the part of the system that causes 90 per cent of everyday smells.

A five‑minute routine that keeps smells away for weeks

Doing the bowl flush once usually gives instant relief. The clever bit is turning it into a tiny routine so the smell doesn’t slowly creep back.

We’ve all had that moment when you promise yourself you’ll “stay on top of it this time” and then life happens. The trick is to tie this to something you already do.

The once‑a‑week reset

Pick a day – Sunday evening after the big roast, or the night you always batch‑cook – and:

Scrape plates properly into the bin or compost before washing.
Wipe oily pans with a bit of kitchen roll before they see any water.
Once the washing‑up is done and the sink is empty, do two rounds of the hot‑water bowl flush.

It’s dull, domestic magic: five minutes now instead of mystery smells and panicked Googling later.

Tiny habits that make a big difference

On top of the weekly flush, these small changes stretch out the freshness:

Use a sink strainer. A simple mesh basket over the plug stops bigger bits (rice, coffee grounds, veg peelings) ever getting into the pipes.
Never pour fats straight down. Let roasting tin fat set in a jar or tin and bin it, rather than rinsing it away hot. Liquid fat turns into a solid plug lower down.
Run hot, not just cold. After rinsing something greasy, finish with 20–30 seconds of hot water to stop fat setting in the trap.
Keep under‑sink cupboards dry. A musty smell can sometimes be a tiny leak. If the area under the sink is damp, fix that first.

None of this is glamorous. But together with the washing‑up bowl flush, it’s usually enough to keep ordinary kitchen drains smell‑free for weeks at a time.

When a smelly drain means you do need a plumber

The washing‑up bowl trick is brilliant for everyday pong caused by build‑up in the trap or the first bit of pipe. It can’t fix everything, and there are moments when a professional is exactly who you need.

Pay attention if you notice:

Gurgling and slow draining even after two or three good hot‑water flushes
Smells coming from more than one drain (for example, kitchen and bathroom at once)
A strong, constant rotten‑egg smell that doesn’t fade – this can be sewer gas, not just stale dishwater
Water pooling under the sink or damp, swollen chipboard in the cupboard

Those signs suggest a deeper blockage, a damaged trap, or an issue in the main waste line. No amount of hot water – or supermarket gel – will safely sort that. It’s time to call someone who can check the pipework properly.

Think of the bowl trick as your first line: cheap, quick, and surprisingly effective. If it doesn’t help, you’ve lost ten minutes and saved yourself pointlessly pouring half a chemistry set down the sink before ringing a plumber anyway.

FAQ:

How often should I do the washing‑up bowl flush?
For most households, once a week is plenty. If you cook a lot of oily or saucy food, you might find a quick flush twice a week keeps smells at bay.

Can I use boiling water straight from the kettle?
It’s better to mix kettle water with hot tap water so it’s very hot but not freshly boiling. Boiling water can be a bit harsh on some plastic fittings and seals, especially in older kitchens.

Does this work on bathroom sinks as well?
Yes, as long as the basin and plumbing are sound. Hair is a bigger culprit in bathrooms though, so you may need a small hair catcher and, occasionally, a manual clear‑out of the trap if it’s accessible.

Is this enough if my drain is already partially blocked?
If water is standing for ages before it drains, the hot‑water flush might improve things a little but won’t fix a proper blockage. In that case, try a plunger or a manual drain snake first; if it’s still bad, call a plumber.