Why Does My Washing Machine Smell Like Mildew And How To Fix It Quickly

A washing machine should represent cleanliness—yet nothing is more unsettling than opening the door and being greeted by a musty, damp odor reminiscent of old gym socks or a basement after rain. If your washing machine smells like mildew, you're not alone. Millions of households face this issue, especially with high-efficiency (HE) front-loading models. The problem isn't just unpleasant—it can transfer odors to your clothes, defeat the purpose of laundering, and even signal underlying hygiene or mechanical concerns.

Mildew thrives in dark, moist environments with organic residue. Unfortunately, modern washing machines—designed for water efficiency—often trap moisture and detergent buildup, creating the perfect breeding ground. The good news? This issue is both fixable and preventable. With the right knowledge and routine, you can restore freshness to your appliance in under an hour and keep it smelling clean long-term.

Why Mildew Forms in Washing Machines

Mildew is a type of fungus that grows in humid, poorly ventilated areas. Unlike mold, which often appears as black or green spots, mildew typically presents as a powdery white or gray substance accompanied by a stale, earthy smell. In washing machines, several factors contribute to its development:

• Trapped Moisture: Front-loaders are especially prone because the rubber door gasket seals tightly, preventing proper air circulation after cycles.
• Detergent Residue: Excess soap, especially in HE machines, doesn’t fully rinse away and clings to seals, drums, and hoses.
• Low-Temperature Washes: While energy-efficient, cold water cycles don’t kill bacteria or dry out internal components.
• Infrequent Use: Leaving the machine idle allows moisture to stagnate, encouraging microbial growth.
• Dirty Filters and Drains: Accumulated lint, hair, and grime become food sources for microbes.

Even top-loading machines aren’t immune. Over time, hard water minerals, fabric softener buildup, and infrequent cleaning create similar conditions in the drum and pump areas.

“Modern washing machines are victims of their own efficiency. Less water and lower temperatures save resources but leave behind residues that fuel biological growth.” — Dr. Linda Harper, Microbiologist & Appliance Hygiene Researcher

Step-by-Step Guide to Eliminate Mildew Smell

Fixing a smelly washing machine doesn’t require professional help in most cases. Follow this detailed, proven process to deep-clean your appliance and remove the odor at its source.

1. Unplug and Prepare
   For safety, disconnect the power. Remove any laundry, cleaning tablets, or dispensers from the machine.
2. Clean the Door Gasket (Front-Loaders)
   Lift the rubber seal around the door and inspect for black specks, slime, or trapped debris. Wipe thoroughly with a microfiber cloth soaked in a solution of one part white vinegar and two parts water. Pay special attention to folds and crevices where water pools.
3. Remove and Clean the Detergent Dispenser
   Slide out the drawer and disassemble if possible. Soak in warm vinegar water for 20 minutes, then scrub with an old toothbrush to remove sludge. Rinse and dry completely before reinserting.
4. Clean the Drain Pump Filter
   Locate the filter (usually behind a small access panel at the bottom front). Place a towel underneath to catch water. Open slowly and remove lint, coins, or gunk. Flush under running water and reinstall.
5. Run a Hot Cleaning Cycle
   Set the machine to the hottest, longest cycle (typically “Clean Washer” or “Sanitize”). Add either:
   • Two cups of white distilled vinegar, OR
   • One cup of bleach (only if your machine manual permits it), OR
   • A commercial washing machine cleaner (e.g., Affresh, Tide Washing Machine Cleaner).
6. Wipe Down Interior Surfaces
   After the cycle, use a vinegar-dampened cloth to wipe the drum, door, and edges. Leave the door and detergent drawer slightly open to dry.
7. Deodorize with Baking Soda (Optional)
   Run a second short cycle with one cup of baking soda added directly to the drum. This neutralizes lingering odors and helps break down organic films.

Tip: Never mix vinegar and bleach—they produce toxic chlorine gas. Use one or the other, never both in the same cleaning session.

Prevention Checklist: Keep Your Machine Fresh Long-Term

Eliminating the smell is only half the battle. To prevent recurrence, integrate these habits into your routine:

• ✅ Leave the door and detergent drawer open after every use to allow airflow.
• ✅ Use high-efficiency (HE) detergent only—and measure carefully. Too much creates excess suds and residue.
• ✅ Avoid overloading; clothes need space to agitate and rinse properly.
• ✅ Wipe the door gasket weekly with a dry or vinegar-dampened cloth.
• ✅ Run a cleaning cycle monthly using vinegar or a dedicated cleaner.
• ✅ Switch fabric softener sheets for wool dryer balls to reduce chemical buildup.
• ✅ Clean the lint filter and drain hose every three months.
• ✅ Wash towels, underwear, and workout clothes at higher temperatures when possible.

Do’s and Don’ts: What to Avoid When Cleaning Your Washer

Do’s	Don’ts
Use distilled white vinegar for cleaning and deodorizing.	Use apple cider vinegar—it may leave sticky residues.
Run hot water maintenance cycles monthly.	Ignore persistent odors—this could indicate mold in hoses or behind the drum.
Measure HE detergent precisely using the cap or scoop.	Pour liquid detergent directly into the drum instead of the dispenser.
Store wet clothes no longer than 30 minutes post-wash.	Leave damp laundry sitting overnight—this breeds bacteria in the drum.
Inspect and clean the filter quarterly.	Use abrasive pads on stainless steel drums—they cause scratches that harbor bacteria.

Real Example: How Sarah Fixed Her Smelly Washer in One Weekend

Sarah, a busy mother of two in Portland, noticed her towels were coming out with a sour smell despite using premium detergent. Her front-loading LG washer had developed a persistent mildew odor that worsened over two months. Initially, she blamed the detergent and switched brands twice—only to see no improvement.

After reading about vinegar cleaning methods online, she decided to take action. On a Saturday morning, she removed the detergent drawer and was shocked to find thick, slimy residue underneath. She soaked the parts, cleaned the gasket thoroughly, and ran a 90°C cycle with two cups of vinegar. After the cycle, she wiped down the drum and left the door open. By evening, the smell was gone. She now runs a cleaning cycle every four weeks and keeps the door ajar—even when not in use. Six months later, her clothes come out consistently fresh.

Her experience underscores a common mistake: assuming the problem lies with laundry products when the root cause is inside the machine itself.

Frequently Asked Questions

Can I use lemon juice instead of vinegar?

While lemon juice is acidic, it contains sugars and pulp that can feed bacteria or leave behind sticky residues. Distilled white vinegar is preferred because it’s pure acetic acid with no additives, making it more effective and less likely to cause secondary issues.

Why does my washer smell only after certain loads?

This often happens when washing heavily soiled items (like gym clothes or baby diapers) at low temperatures. Sweat, oils, and bodily fluids remain in the drum if not properly rinsed or sanitized. Always wash such items at 60°C (140°F) or use a pre-soak cycle with oxygen-based cleaner.

Is it safe to use bleach in my washing machine?

Bleach is effective for disinfecting but should only be used in machines approved for it (check your manual). Never mix bleach with vinegar or ammonia-based cleaners. Use sparingly—once every few months—and always follow with a rinse cycle. Overuse can degrade rubber seals and hoses over time.

When to Call a Professional

Most mildew smells resolve with diligent cleaning. However, persistent odors after multiple cleaning attempts may indicate deeper problems:

• Mold in internal hoses or behind the drum
• Clogged or damaged drain pump
• Cracked door gasket allowing water leakage into cabinet walls

If you notice visible mold outside accessible areas, hear unusual noises during drainage, or detect dampness around the base of the machine, contact a certified technician. Some issues require disassembly and cannot be safely handled without tools and expertise.

Tip: Take photos during cleaning sessions. Documenting residue levels helps track progress and identify recurring issues early.

Conclusion: A Fresh Washer Starts with Smart Habits

Your washing machine works hard for you—don’t let it become a source of contamination. The mildew smell is more than a nuisance; it’s a sign that hygiene standards are slipping. The solution isn’t complicated, but it does require consistency. By understanding how mildew forms, taking prompt action to clean affected areas, and adopting preventive routines, you can maintain a truly clean appliance.

Start today: run a cleaning cycle, wipe the gasket, and leave the door open. These small steps yield immediate results and long-term protection. A fresh-smelling washer means fresher clothes, better hygiene, and peace of mind. Don’t wait for the stench to return—make washer maintenance a non-negotiable part of your home care routine.

💬 Have a tip that worked for your smelly washer? Share your experience in the comments below—your insight could help another household breathe easier.