A wet mattress is a race against mold. Mold and mildew can begin establishing in damp material within roughly 24 to 48 hours, and once it is growing inside the foam or padding you cannot reliably clean it out. Everything below is organised around beating that clock.
The other thing to understand up front: mattresses are extremely good at holding water. Foam in particular acts like a sponge, and the surface can feel dry while the core is still saturated. Most people stop drying far too early.
The first hour matters most
Do these four things before you gather any supplies.
- Strip the bed completely. Sheets, protector, topper, everything. Wet bedding sitting on a mattress keeps feeding water into it. Get it all into the washing machine.
- Stop the source. A knocked-over glass is one thing. A roof leak or a burst supply line will keep going, and drying under an active drip is wasted effort.
- Blot, do not rub. Press clean dry towels straight down into the wet area and hold. Rubbing works water sideways and deeper into the foam. Stand on the towel if you need more pressure. Swap towels the moment one stops taking up water.
- Get the mattress off the base. Stand it on its side, ideally against a wall with a towel underneath. This does two things at once: it stops water draining into the foundation or bed frame, and it exposes both faces to air. On a soaked mattress this single step does more than anything else you will do.
What you need
- A stack of dry towels, more than you think
- A wet/dry shop vacuum if you have access to one, which is the single most useful tool here
- Two or three fans
- A dehumidifier if you have one
- Baking soda
- A vacuum with an upholstery attachment
Note what is not on that list: a hair dryer on hot, a heat gun, and a space heater pointed at the bed. Heat that high can damage foam and adhesives, and warm damp foam is an ideal environment for mold rather than a hostile one. Moving air beats hot air every time.
Pull out the standing water
If more than a cupful went in, a wet/dry vacuum is worth borrowing, renting or buying. Run the nozzle slowly across the wet area in overlapping passes, pressing down enough to compress the surface and draw water up out of the layers underneath. Repeat on the underside.
Keep going past the point where the surface stops looking wet. Press a dry paper towel firmly into the area and look at it. If any moisture transfers, there is still water in there.
Without a wet vac, you are relying on towels and pressure. Lay a towel over the area, stand on it, wait, and replace it. It works, it just takes far longer and gets less of the deep water out.
Dry it out, properly
Airflow is the whole game. Aim two or three fans at the mattress from different angles, with at least one blowing across the face rather than straight at it. Keep it standing on edge so both sides are exposed. Open the windows if the air outside is dry, which in Los Angeles it usually is. If the room is humid, close it up and run a dehumidifier instead, since a fan just moves damp air around.
Sunlight helps and is mildly antimicrobial, so a few hours outside on a dry day is worth the effort. Do not leave it out all day: prolonged UV degrades foam and fabric, and an unattended mattress in the afternoon is a target for dust, insects and a surprise sprinkler.
How long this takes. A small spill on a protected mattress can be dry in a few hours. A full soaking through to the core realistically takes two to four days of continuous airflow, and a thick memory foam mattress can take longer. Do not rush it and do not trust a dry-feeling surface.
Baking soda, used correctly
Baking soda is a finishing step, not a drying method. It absorbs a modest amount of residual moisture and it does neutralise odours well, but it will not pull water out of a saturated core.
Use it once the mattress is mostly dry. Sprinkle a generous layer over the affected area, leave it for several hours or overnight, then vacuum it up thoroughly with an upholstery attachment. If you put it on while the mattress is still properly wet, it clumps into a damp paste that is difficult to remove and holds moisture in place. Our guide to cleaning a mattress covers the technique in more detail.
It depends what the water was
Clean water from a glass, a bottle or a supply-line leak is the straightforward case. Dry it and you are finished.
Urine needs an enzyme cleaner, not just drying. The uric acid crystals that cause the lingering smell are not water-soluble and will reactivate every time the spot gets humid. See how to clean pee out of a mattress for the full method.
Greywater or floodwater is the one case where the answer is usually to stop. Water from a washing machine, a dishwasher, a backed-up drain or outdoor flooding carries bacteria and contaminants deep into material you cannot disinfect all the way through. A porous mattress that has been soaked in contaminated water should be replaced, not dried.
It also depends what the mattress is
Memory foam and all-foam. The hardest to save. Foam absorbs enormous amounts of water and releases it slowly, and a thick comfort layer can stay wet inside for days after the surface feels fine. Never put weight on a wet foam mattress beyond blotting pressure, since saturated foam tears. See cleaning a memory foam mattress for the specifics.
Innerspring and hybrid. Better odds, because air moves through the coil layer and speeds drying. The catch is that steel rusts. If a coil unit stays wet for days you may end up with rust stains and, eventually, squeaking, even after the padding dries.
Latex. Naturally more resistant to mold than polyurethane foam, but still dense and slow to dry. Keep it out of direct sun for long periods, since UV degrades latex faster than other materials.
Pillow top. Awkward, because the quilted comfort layer traps water against the mattress below and dries slowly. Give it more time than you think it needs.
Do not forget what was underneath
Water that went through the mattress went somewhere. Check the foundation, box spring, slats and the floor beneath the bed. A damp box spring will simply re-wet a dry mattress and is easy to overlook, since the fabric-covered wooden frame holds moisture well and shows very little on the outside. Dry it the same way, standing on edge with air moving across it. Carpet under the bed needs attention too.
When to stop trying and replace it
Be honest about this one. A mattress you cannot fully dry is a health problem rather than a bargain.
- You can see mold. Black, green or grey spotting means it has already colonised material you cannot reach. Replace it.
- A musty smell persists after it is dry. That smell is microbial growth, not residual damp.
- It was soaked in contaminated water. Flood, sewage or greywater. Not worth the risk.
- It is still damp after four or five days of proper drying. At that point the mold clock has run out.
- Anyone in the house starts getting congested, wheezy or itchy after you put the bed back together.
Worth checking your warranty before you spend money on drying equipment, though be aware that most mattress warranties specifically exclude liquid damage and staining. Our guide to mattress warranties explains what is typically covered. If it does need to go, disposing of a mattress in Los Angeles covers the free recycling options.
Stop it happening again
A waterproof mattress protector is the cheapest insurance in bedding. It turns a four-day drying operation into wiping a surface and running a load of laundry, and a good one is breathable enough that you will not notice it is there. If you have kids, pets, or a habit of reading in bed with a drink, it pays for itself the first time. Our guides on whether you need a mattress protector and the difference between a protector and a pad cover what to look for.
Frequently asked questions
How long does a wet mattress take to dry?
A small surface spill on a protected mattress can be dry within a few hours. A mattress soaked through to the core takes two to four days with fans running continuously, and a thick memory foam mattress can take longer still. The surface always dries first, so test by pressing a dry paper towel firmly into the spot and checking it for moisture rather than going by feel.
Can a wet mattress be saved?
Usually yes, if the water was clean and you start within the first few hours. The odds drop sharply after 24 to 48 hours, which is when mold begins to establish. A mattress soaked in floodwater, sewage or greywater should be replaced regardless of how quickly you act, because you cannot disinfect the inside of a porous material.
Can you use a wet vac on a mattress?
Yes, and it is the most effective tool for the job. Use a wet/dry shop vacuum, not a regular household vacuum, which is not built for liquid and can be damaged or create a shock hazard. Work in slow overlapping passes with enough downward pressure to compress the surface and draw water up from the layers underneath, then repeat on the other side.
Can you put baking soda on a wet mattress?
Wait until it is mostly dry. Baking soda on properly wet foam turns into a damp paste that is hard to vacuum out and holds moisture against the mattress, which is the opposite of what you want. Once the bulk of the water is gone, a generous layer left overnight absorbs residual moisture and does a genuinely good job on odour.
How do you clean a mattress that got wet from bedwetting?
Drying alone will not solve it. Urine leaves uric acid crystals that are not water-soluble, so the smell returns whenever the spot gets warm or humid. Blot up as much liquid as possible, then treat the area with an enzyme cleaner made for pet or urine stains and let it sit long enough to break the crystals down before you start drying.
Does wetting the bed ruin the mattress?
Not if you deal with it promptly. A single accident treated with an enzyme cleaner and dried properly leaves no lasting damage. Repeated accidents that are not fully cleaned each time are what ruin a mattress, because the residue builds up in the padding. If bedwetting is a regular occurrence, a waterproof protector is essential rather than optional.
Should I use a hair dryer to dry a mattress?
Only on a cool setting, and only for small damp patches. High heat can damage foam and the adhesives holding the layers together, and warm damp foam encourages mold rather than preventing it. Fans moving air across the surface dry a mattress far more effectively than heat does.
How do I know if my mattress has mold?
Look for black, green or grey spotting, particularly on the underside and along the seams. A persistent musty smell after the mattress is fully dry is the other reliable sign, and it often shows up before anything is visible. New or worsening congestion, coughing or itchy eyes that ease when you sleep elsewhere is worth taking seriously too. If you find mold, replace the mattress. Surface cleaning does not reach what is growing inside.
If it is beyond saving
Water damage is a miserable reason to need a new mattress, but it is also a chance to fix whatever was not quite right about the old one. Come lie on a few at any of our five Los Angeles showrooms, or take our sleep quiz if you would rather narrow it down first. We deliver same day across LA, we will haul the old mattress away, and every mattress comes with a free 120-night comfort guarantee. Our current offers are worth a look if the timing was not your choice.
