Why Does My Washing Machine Smell Like Mildew Simple Fixes To Clean The Filter

If you’ve opened your washing machine only to be greeted by a damp, musty odor reminiscent of a basement after rain, you’re not alone. Mildew smells in washing machines are surprisingly common—especially in high-efficiency (HE) models—and they can transfer that unpleasant scent directly onto your clothes. The root cause often lies in moisture buildup, detergent residue, and, most critically, a clogged or dirty filter. The good news: this issue is both preventable and fixable with routine maintenance and a few smart habits.

Unlike older top-loading machines that fully drained water, modern front-load washers seal tightly and retain small amounts of moisture. This environment, combined with leftover lint, soap scum, and organic matter, creates the perfect breeding ground for mold and mildew. While many assume the drum or detergent drawer is the main culprit, the filter—a small but vital component—is frequently overlooked. When blocked, it traps stagnant water and debris, accelerating bacterial growth and foul odors.

This guide breaks down why your washing machine develops mildew smells, how to locate and clean the filter properly, and what long-term steps to take to keep your appliance fresh and functioning efficiently.

Understanding the Source of the Smell

Mildew and mold thrive in dark, damp environments with organic material to feed on. Your washing machine provides all three:

• Moisture: Residual water lingers in seals, hoses, and the sump area.
• Organic Matter: Hair, lint, skin cells, and fabric fibers accumulate over time.
• Warmth: Heat from cycles and ambient room temperature accelerates microbial growth.

The rubber door gasket on front-load machines is a notorious trap for water and grime. Over time, black specks may appear—this is often mold forming along the folds. But while the gasket needs attention, the filter plays an even more critical role in odor control.

The filter, also known as the drain pump filter or sump filter, catches foreign objects like coins, buttons, and lint before they enter the pump. When neglected, it becomes a reservoir for sludge and standing water. Even if your machine drains properly, a partially clogged filter can retain moisture for days, creating a stinking swamp beneath the drum.

“Most washing machine odors stem from poor drainage and trapped debris. Cleaning the filter isn’t just about performance—it’s essential hygiene.” — Dr. Lena Patel, Appliance Hygiene Specialist

How to Locate and Clean the Washing Machine Filter

Cleaning the filter is one of the most effective ways to eliminate mildew smells. However, many homeowners don’t know where it is or how to access it safely. The process varies slightly by brand, but the general steps are consistent.

Step-by-Step Guide to Cleaning the Filter

1. Unplug the Machine: For safety, disconnect power before starting.
2. Prepare for Water: Place towels around the base. Have a shallow tray or bucket ready—up to 2 cups of water may spill out.
3. Locate the Access Panel: On most front-loaders, the filter is behind a small rectangular panel at the bottom front of the machine. Some brands (like Samsung or LG) have a twist-lock cover; others (like Whirlpool or Bosch) require removing screws.
4. Open Slowly: Unscrew the filter cap counterclockwise. As you loosen it, water will begin to drain. Let it empty completely before removing the filter.
5. Remove and Inspect the Filter: Pull out the mesh or plastic filter. Check for hair, coins, socks, or thick sludge.
6. Clean Thoroughly: Rinse under warm water. Use an old toothbrush to scrub away residue. For stubborn buildup, soak in a mix of vinegar and water (1:1) for 15 minutes.
7. Check the Sump Area: Shine a flashlight into the opening. If you see debris, remove it with gloves or tweezers.
8. Reinstall Securely: Slide the clean filter back in and tighten the cap by hand. Do not overtighten.
9. Run a Cleaning Cycle: Plug the machine back in and run a hot cycle (90°C/194°F) with no clothes. Add 1 cup of white vinegar or a washing machine cleaner to flush remaining residue.

Tip: Mark your calendar to clean the filter every 1–2 months, especially if you do multiple loads per week.

Common Mistakes That Worsen the Problem

Even with regular use, some habits accelerate mildew development. Avoid these pitfalls:

Mistake	Why It’s Harmful	Better Alternative
Using too much detergent	Excess suds trap moisture and leave sticky residue that feeds bacteria	Use HE-rated detergent and follow dosage instructions
Leaving wet clothes in the drum	Traps humidity and transfers odor to next load	Remove laundry immediately after the cycle ends
Washing at low temperatures daily	Cold water doesn’t kill bacteria or dissolve oils effectively	Run a hot cycle monthly to sanitize the drum
Ignoring the door seal	Mold grows in the rubber folds, especially in damp climates	Wipe the gasket weekly with a vinegar-dampened cloth
Blocking ventilation around the machine	Prevents airflow, prolonging drying time inside the unit	Leave at least 2–3 inches of space behind and beside the washer

Real Example: How One Family Fixed Their Smelly Washer

The Thompson family in Portland, Oregon, noticed their towels started smelling sour after washing. They used eco-friendly detergent and washed mostly in cold water to save energy. After ruling out water quality issues, they inspected the machine and found the rubber gasket was swollen with black mold. They cleaned it with a baking soda paste, but the odor returned within weeks.

A technician suggested checking the filter—an area they’d never touched. Upon removal, they discovered a tangled mass of pet hair, a lost earring, and thick, muddy sludge. After cleaning the filter and running two hot vinegar cycles, the smell vanished. Since then, they’ve maintained a monthly cleaning schedule and open the door after each use to air out the drum. Two years later, their washer runs quietly and smells neutral.

Preventative Maintenance Checklist

To avoid recurring mildew smells, adopt these habits as part of your household routine:

• ✅ Clean the filter every 4–8 weeks
• ✅ Wipe the door gasket with a dry or vinegar-dampened cloth weekly
• ✅ Leave the door and detergent drawer open after each use
• ✅ Run a maintenance cycle with vinegar or a dedicated cleaner monthly
• ✅ Use the correct amount of HE detergent—never pour liquid directly into the drum
• ✅ Remove laundry promptly and avoid overloading
• ✅ Inspect hoses annually for cracks or leaks
• ✅ Replace the inlet filters (on hose connections) every 6 months if accessible

Tip: Place a moisture-absorbing pack (like silica gel) near the detergent drawer when not in use to reduce humidity.

Frequently Asked Questions

Can I clean the filter without spilling water?

No—some water release is unavoidable. Always prepare with towels and a container. To minimize spills, let the machine sit for 30 minutes after a cycle so water settles. Never attempt to remove the filter during or right after a wash.

My machine doesn’t seem to have a filter. Where is it?

Some newer models have self-cleaning pumps or hidden filters requiring professional service. Consult your user manual. If no access panel exists, your model may rely on internal filtration, making regular cleaning cycles even more important.

Is bleach safe for cleaning a smelly washing machine?

Yes, but with caution. Chlorine bleach can degrade rubber seals over time. For routine cleaning, white vinegar or citric acid-based cleaners are gentler and equally effective at breaking down biofilm. Reserve bleach for deep sanitizing once or twice a year, and never mix it with vinegar.

Final Thoughts: A Fresh Washer Starts with Small Habits

A mildew-smelling washing machine isn’t just unpleasant—it’s a sign of underlying hygiene issues that can affect your clothes, allergies, and appliance lifespan. While cleaning the filter is a powerful first step, lasting freshness comes from consistent care. Think of your washer like a kitchen sink: it handles waste and moisture daily, so it needs regular attention to stay clean.

By integrating simple practices—like wiping seals, using the right detergent, and scheduling filter cleanings—you prevent problems before they start. These efforts take minutes but extend your machine’s life and ensure your laundry comes out truly clean, not just technically washed.

💬 Take action today: Check your filter this week and run a hot cleaning cycle. Share your experience or tips in the comments—your insight could help another homeowner banish that stubborn mildew smell for good.