It's 2am, the bed is soaked, and you need this sorted before morning. To get urine smell out of a mattress: strip the bedding and wash it hot, blot the urine without rubbing, lightly spray a white vinegar and water solution, blot again, cover the area with bicarbonate of soda for a few hours, then vacuum it off. If the smell lingers, repeat the steps or use an enzyme cleaner.
For parents and carers dealing with accidents on a child's or teenager's mattress, acting fast usually saves the bed. Leave it and the uric acid crystallises, which is what makes that ammonia smell come back every time the room warms up. This guide shows you how to clean and dry the mattress properly, when a mattress is too far gone to keep, what to do with bunk beds and high sleepers, and how to stop it happening again with protectors, waterproof mattresses and simple mattress care.
What you'll need: white vinegar, bicarbonate of soda, a spray bottle, old towels and, for stubborn smells, an enzyme cleaner.
On this page
Right now: the first five minutes
Strip the bed
Sheets, protector, everything. Straight into the machine on a hot wash.
Blot, don't rub
Press down hard with a towel until it stops lifting moisture. Rubbing pushes urine deeper into the foam, and it's the most common mistake.
Don't soak it
Whatever you use next, damp is enough. Over-wetting a foam mattress causes mould, which is far harder to deal with than the original problem.
On a top bunk or high sleeper? Bring the mattress down to the floor before you start. Here's why.
The method that works: vinegar and bicarbonate of soda
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1
Spray
Mix equal parts white vinegar and cold water in a spray bottle. Mist the area until it's slightly damp. The acid breaks down the alkaline compounds in urine, which is why vinegar works where soap doesn't.
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2
Wait, then blot
Leave it 10 minutes, then blot with a dry towel.
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3
Cover with bicarbonate of soda
Be generous: it should look like snow. Leave it as long as you can, ideally overnight, and at least four hours.
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4
Vacuum it off
Use the upholstery attachment and lift every bit of powder.
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5
Repeat if you can still smell it
Dried-in accidents often need two or three passes.
Drying it properly
This is where most people undo their own work. Open a window, get a fan on it, and leave the bedding off until the mattress is dry all the way through. Press a dry towel into the area to check for damp. On a foam mattress, allow a full day.
Stain still showing once it's dry? A little hydrogen peroxide can lift it. Patch test it on a hidden corner first, as it can lighten some fabrics, and never mix it with vinegar or any other cleaner.
If the smell keeps coming back
That means uric acid crystals are still in there, and vinegar alone won't shift them. Use an enzyme cleaner, which breaks down the compounds causing the smell instead of just covering it up. You'll find them in most supermarkets and pet shops, and pet formulas work just as well on human urine. Follow the label and let the mattress dry fully before making the bed.
Avoid bleach entirely. It damages the fabric, can degrade foam, and doesn't touch the uric acid.
Dealing with this most nights? A protector only goes so far. The DryComfort 15 is waterproof all the way through, so nothing reaches the foam: wipe it down and remake the bed. 15cm deep, made in the UK and delivered rolled.
Bunk beds and high sleepers: a word of warning
If the accident is on a top bunk or high sleeper, don't try to clean it in place. Water running down into the frame is a genuine problem, and reaching across a guard rail with a spray bottle is how people fall.
Take the mattress down to the floor, clean it there, and let it dry flat before putting it back. Awkward, but far better than the alternative.
When a mattress can't be saved
Sometimes it's beyond cleaning, and it's worth knowing when to stop. Replace it if:
- the smell returns every time the room warms up, after two or three thorough cleans
- there's visible mould or dark staining under the cover
- it's been soaked through repeatedly over months
- it's more than seven or eight years old anyway
There's no prize for saving a mattress your child is sleeping on unhappily. If you're at that point, have a look at our kids' mattresses. For a bunk bed or high sleeper, choose one within the bed's maximum mattress depth, usually 15 to 16cm, so the guard rail stays at a safe height. Our PocketRest 15, MemoryDream 15, ComfortSleep 15 and DryComfort 15 are all 15cm deep, made in the UK, and arrive rolled so they go upstairs easily. Our bunk bed mattress guide explains sizes and depths.
Stopping it happening again
Two levels of protection, depending on how often you're dealing with this.
Occasional accidents
A waterproof protector
It sits between the sheet and the mattress and stops urine soaking in. It goes in the washing machine, the mattress stays dry, and you're changing bedding at 2am rather than cleaning foam. Choose one that fits snugly; the better ones are quiet and don't feel plasticky.
If you buy nothing else after reading this, buy one of these. It costs a fraction of a new mattress.
See the waterproof protector
Regular accidents
A waterproof mattress
During potty training or a bedwetting phase, a protector alone can struggle. A heavy accident finds the edges, and you're back to cleaning the mattress underneath.
The DryComfort 15 is waterproof all the way through, not just a cover laid over the top, so nothing reaches the foam. Wipe it down, remake the bed, done.
It's a proper mattress underneath, with a reflex foam comfort layer over a supportive base. At 15cm deep it suits most bunk beds and high sleepers; always check your bed's maximum mattress depth, and for a trundle, the trundle's. The cover comes off for washing, and it's made in the UK in eight sizes, from shorty to continental double.
See the DryComfort 15The practical stuff
- Double-layer the bed. Protector, sheet, second protector, second sheet. At 2am you strip one layer off and there's a made bed underneath.
- Last drink an hour before bed, and a final toilet trip as part of the routine.
- Keep spares to hand. A clean set of bedding in the room means five minutes rather than twenty.
And worth saying plainly: bedwetting is normal well into primary school and it isn't anyone's fault. If it's causing real worry, your GP or health visitor will have seen it a thousand times.
Keeping on top of it
| Monthly | Vacuum the mattress, sprinkle bicarbonate of soda, leave an hour, vacuum off. |
|---|---|
| As needed | Spot clean using the method above. |
| Annually | A deeper clean, and check the mattress is still supportive. See how often you should change a mattress. |
More on this in our guide to cleaning a mattress properly.
Common questions
Can I use bleach?
No. It damages the fabric, can break down foam, and doesn't remove the uric acid causing the smell. Vinegar, bicarbonate of soda and enzyme cleaner are what work.
Why does the smell come back when the room is warm?
Uric acid crystals left in the mattress reactivate with heat and humidity. It means the cleaning didn't reach them, and an enzyme cleaner is the answer.
Can I clean an old, dried-in stain?
Usually, yes. It takes longer and often two or three passes. Start with the enzyme cleaner rather than vinegar, since the crystals have set.
Is a memory foam mattress harder to clean?
Yes. Foam absorbs faster and dries slower, so use less liquid and allow a full day of drying. Never soak it.
Should I get a protector or a waterproof mattress?
A protector for occasional accidents. A waterproof mattress like the DryComfort 15 if it's happening regularly, or if you'd rather not think about it at all.
How often should I clean my mattress?
Vacuum and deodorise monthly, spot clean as needed, deep clean once a year.
