Verdict: Partly true. Whirlpool says a few hours usually doesn't hurt, but the longer clean, wet laundry sits in a closed drum, the greater the chance of mildew and a musty smell that can spread to the washer itself.
Where the idea comes from
Most people have done it. A load finishes late, nobody hears the chime, and the clothes sit until morning. Often they smell fine, which makes it easy to believe that time in the drum doesn't matter.
The opposite belief also circulates: that any load left more than an hour must be rewashed. Neither extreme matches what manufacturers say.
What the evidence says
Whirlpool's article on clothes left in the washer overnight says that "usually, a few hours doesn't hurt," and that longer stays raise the risk of mold and mildew developing. It notes that the odor can transfer to the washer. Its test is simple: sniff a handful of items, and if any have an odor, rewash the whole load before drying. For stubborn smells, it suggests another full cycle with a presoak option.
Whirlpool's washer care page on removing odors from the interior of a washer puts the habit in plain terms: "Unload the washer as soon as the cycle is complete." The same page advises leaving the lid or door open between uses so the washer can dry out.
LG's odor guidance makes the same connection from the machine's side. Its page on washer odor recommends a monthly tub clean cycle and leaving the door open to dry after wiping the gasket.
So the belief holds up for a short delay and breaks down for a long one. No source gives an exact cutoff, which is why the smell test matters.
What to do instead
- Use the smell test. Pull a few items from the middle of the load, not just the top.
- If anything smells sour or musty, rewash the whole load before it goes in the dryer. Drying sets the smell.
- If the load smells clean, dry it right away.
- Leave the door open and wipe the gasket afterward, since the drum was closed and damp for hours.
- Next time, use a delay-start or app alert if your washer has one, so the cycle ends when you're home.
Exceptions worth knowing
- •Front-loaders hold moisture longer because the door seals tightly, so a closed front-loader is the worst place for wet laundry to sit.
- •Some washers have a feature for this. Whirlpool describes a FanFresh option on select models that uses a fan and periodic tumbling to keep washed clothes fresh until you can dry them.
- •Warm rooms speed things up. A garage laundry in an inland heat wave is a less forgiving place than a cool hallway closet.
- •A washer that smells even when you unload promptly needs cleaning or a closer look. See how often a washer really needs a cleaning cycle.
Sources
- •Whirlpool: What to do with clothes left in the washer overnight (a few hours; sniff test; rewash; FanFresh)
- •Whirlpool: Removing Odors from the Interior of a Washer (unload promptly; leave the door open)
- •LG: Washer odor (monthly tub clean; door open to dry)
The short version: A few hours is usually fine, overnight is a gamble, and your nose decides whether to rewash.
A washer that smells musty even when you unload it right away needs a closer look. TrueFix Los Angeles works in Koreatown and Westlake and the surrounding neighborhoods; call (213) 787-3989.