Your Clothes Are Clean—So Why Do They Still Smell Bad? Experts Explain

Taking a whiff of freshly washed laundry only to find it smelling more sour than clean is a uniquely unpleasant experience—but not an entirely uncommon one. Even when you follow your usual laundry care routine, a stubborn musty scent can linger and the culprit isn’t always one single issue.

"Laundry smells are usually caused by buildup, whether it’s from detergent, softener, or mildew in the washer," explains Stephanie Phillips, owner of Phillips Commercial and Residential Cleaning in Nashville, TN. "Once you address where that buildup comes from, the fix is usually quick and simple."

Understanding what's behind the odor is the first step toward ridding it from fabrics for good—and a few simple tweaks can keep every load smelling clean and fresh.

Odor Origin #1: Detergent and Fabric Softener Buildup

Using too much detergent or the wrong kind for your machine can actually make laundry smell worse—not better. Excess soap traps residue in fabrics, especially in cool or short wash cycles. Over time, that residue becomes a breeding ground for odor-causing bacteria. “People often assume more detergent means cleaner laundry, but the opposite is true,” says Phillips. “The leftover suds can cling to fibers and trap moisture, which starts to smell sour almost immediately.” 

The Fix

Switch to a high-efficiency detergent if you have a front-loading washer, and measure carefully rather than guessing or pouring blindly. Once a month, run an empty hot wash with a cup of white vinegar to help dissolve leftover buildup.

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Odor Origin #2: Hidden Mildew in the Washer

Even a machine that looks spotless or has recently been wiped clean can hide mildew behind the rubber door gasket or inside the detergent drawer. When moisture lingers after each cycle, mold spores can multiply and transfer that musty scent to every load. “Front-load washers are especially prone to mildew because they seal so tightly,” Phillips notes. “That trapped humidity is perfect for growing yucky stuff, especially around the rubber gasket.”

The Fix

After each wash, wipe down the gasket and leave the door open to air dry. Once a week, clean the detergent tray and run a hot water or sanitizing cycle with a commercial washing-machine cleaner or vinegar."When your washer stays fresh, your clothes will, too," notes Phillips.

Odor Origin #3: Wet Laundry Left Sitting in the Machine

If you forget to transfer laundry promptly, damp fabrics quickly develop that sour "wet towel" smell. Even a couple of hours in a closed washer can be enough for a stink to start forming: "That smell happens faster than most people think," says Phillips. "Within just a few hours, bacteria start feeding on the tiny bits of organic material that remain in the fabric.”

The Fix

Setting a timer to remind you when the cycle ends can help prevent odors from forming. "If I leave clothes sitting too long, I usually rewash them with one cup of vinegar in the rinse cycle to neutralize odors, then dry on the highest setting allowed by the fabric," says Phillips. "That’s usually all it takes."

Odor Origin #4: Overloaded Wash Cycles

Stuffing too many items into the drum limits the circulation of detergent and water, resulting in uneven cleaning. “Your washer can’t rinse properly if it’s crammed full,” Phillips says. “You’ll notice that big loads often feel heavier or still damp in places. That’s trapped moisture waiting to turn musty.” 

The Fix

Wash fewer items at a time so they can move freely, and if needed, add an extra rinse cycle to ensure detergent and odors are entirely removed.

Odor Origin #5: Improper Drying Techniques

Even just-laundered clothes will smell musty if they’re put away while slightly damp. Additionally, line-dried laundry can also absorb humidity or outdoor odors if left too long. “If your dryer vent is clogged or your clothes feel cool instead of warm when the cycle ends, that’s a red flag,” says Phillips. “Lingering moisture is the fastest route to that sour smell.”

The Fix

Shake out garments before drying to allow air circulation. If air-drying indoors, use a fan or dehumidifier to speed evaporation. For dryer loads, clean the lint trap after each load and ensure the vent duct is clear for proper airflow.