How To Deeply Clean A Washing Machine That Smells Like Mildew

A washing machine should be the source of freshness, not foul odors. Yet, many homeowners are surprised when they open their washer only to be greeted by a damp, musty smell reminiscent of mildew. This issue is more common than you might think—especially in high-efficiency (HE) models—and it stems from trapped moisture, detergent residue, and organic buildup in hidden areas like the rubber gasket, drum, and drain pump. Left untreated, this mildew odor can transfer to your clothes, making them smell less than clean despite being freshly laundered.

The good news: a deep cleaning process can fully restore your machine’s hygiene and performance. Unlike routine wipe-downs, a thorough clean targets microbial growth at its source. With the right approach, tools, and timing, you can eliminate the mildew smell for good and prevent its return. This guide provides actionable steps, backed by appliance care experts, to help you reclaim a truly fresh washing machine.

Why Washing Machines Develop Mildew Smells

Mildew thrives in warm, moist environments—conditions commonly found inside modern washing machines. While these appliances are designed to clean clothes, their internal components often retain water long after cycles end. The rubber door seal on front-loading machines, in particular, traps moisture and collects lint, hair, and soap scum. Over time, this creates a breeding ground for mold and mildew.

High-efficiency washers use less water than traditional models, which means detergent doesn’t always rinse away completely. Residual surfactants and fabric softeners coat the drum and accumulate in crevices. When combined with humidity, these residues feed microbial colonies that emit volatile organic compounds (VOCs)—the source of the unpleasant odor.

Top-loaders aren't immune either. If left closed between uses or if wet laundry sits too long post-cycle, stagnant water in the basin or drain hose can also lead to mildew development. Even infrequent use contributes to the problem; without regular operation, moisture stagnates and promotes biological growth.

“Many people don’t realize that their washing machine needs maintenance just like any other appliance. A smelly washer isn’t working as effectively—and it may be recontaminating your clothes.” — Dr. Lena Patel, Appliance Hygiene Specialist, National Home Care Institute

Step-by-Step Guide to Deep Cleaning Your Washing Machine

Cleaning a mildew-smelling washing machine requires more than a quick wipe. Follow this comprehensive 7-step process to ensure every part of the machine is sanitized and deodorized.

1. Unplug or disconnect power – For safety, turn off the machine and unplug it, especially if you’ll be accessing internal parts.
2. Remove and clean the rubber gasket (front-loaders) – Pull back the flexible rubber seal around the door. Wipe down both sides with a microfiber cloth soaked in a solution of equal parts white vinegar and water. Use an old toothbrush to scrub crevices where black specks (mildew) appear.
3. Clean the detergent and fabric softener dispensers – Remove trays and soak them in warm, soapy water. Scrub with a brush, rinse thoroughly, and dry before replacing.
4. Inspect and clear the drain pump filter – Locate the access panel (usually at the bottom front). Place a towel underneath, open slowly to catch residual water, and remove the filter. Clean out debris, then flush under running water before reinstalling.
5. Run a hot vinegar wash cycle – Pour 2 cups of distilled white vinegar into the drum (not the dispenser). Run the longest, hottest cycle available (e.g., “Clean Washer” or “Sanitize”). Pause mid-cycle and let the vinegar sit for 30–60 minutes to maximize disinfecting action.
6. Follow with a baking soda scrub cycle – After the vinegar cycle completes, sprinkle ½ cup of baking soda directly into the drum. Run another hot cycle. Baking soda neutralizes lingering odors and lifts greasy residue.
7. Wipe down all accessible surfaces – Once the cycles finish, use a dry microfiber cloth to wipe the door, gasket, rim, and control panel. Leave the door and detergent drawer slightly ajar to promote air circulation.

Tip: Never mix vinegar and bleach—they create toxic chlorine gas. If you’ve used bleach recently, wait at least two weeks before introducing vinegar.

Alternative Cleaning Methods: Commercial Cleaners vs. Natural Solutions

While vinegar and baking soda are widely recommended, commercial washing machine cleaners offer targeted formulations for heavy buildup. Below is a comparison of common cleaning options.

Method	Effectiveness	Cost	Safety Notes
White vinegar + baking soda	High for light-to-moderate buildup	$ (low)	Non-toxic, pet-safe, eco-friendly
Bleach (for non-HE top loaders)	Very high against mold	$$	Use only in well-ventilated areas; never mix with vinegar or ammonia
Commercial cleaner (e.g., Affresh, Tide Washer Cleaner)	High across all machine types	$$$	Follow label instructions; some contain sulfamic acid
Hydrogen peroxide (3%)	Moderate; better for odor than heavy grime	$	Less corrosive than bleach; safe for most materials

Natural solutions are ideal for monthly maintenance, while commercial products may be necessary for machines with chronic odor issues. Always check your manufacturer’s manual—some brands caution against vinegar due to potential damage to rubber seals over time.

Real Example: How One Household Eliminated a Persistent Smell

The Thompson family had been struggling with a sour smell in their three-year-old front-load washer. Towels came out smelling damp, and the machine emitted a swampy odor every time it started. They tried wiping the door and running empty cycles with detergent, but the problem persisted.

After consulting a technician, they learned the root cause: the drain filter was clogged with hair and sludge, and the rubber gasket harbored thick mildew colonies. Following the deep-cleaning steps outlined above—including removing the filter, scrubbing the gasket, and running sequential vinegar and baking soda cycles—the odor disappeared completely. They now leave the door cracked after each use and run a cleaning cycle every four weeks. Two years later, the washer remains odor-free.

Monthly Maintenance Checklist to Prevent Mildew

Prevention is far easier than remediation. Incorporate these habits into your routine to keep your washing machine fresh between deep cleans.

• Leave the door and detergent drawer open after each use to dry out interior surfaces.
• Wipe the rubber seal weekly with a vinegar-dampened cloth.
• Use high-efficiency (HE) detergent only—regular detergents create excess suds and residue.
• Avoid overloading the machine; proper water flow reduces residue buildup.
• Don’t let wet clothes sit in the drum for hours after the cycle ends.
• Run a cleaning cycle with vinegar or a commercial cleaner every 1–2 months.
• Remove and rinse the lint trap (if applicable) quarterly.
• Inspect hoses annually for cracks or leaks.

Tip: Skip liquid fabric softeners—they coat the drum and sensors. Use wool dryer balls or vinegar in the rinse cycle instead.

Frequently Asked Questions

Can I use bleach to clean my washing machine?

Yes, but only in top-loading machines without stainless steel drums. Add 1 cup of bleach to a hot cycle. Do not use bleach in front-loaders unless specified by the manufacturer, as it can degrade rubber seals. Never mix bleach with vinegar or ammonia-based cleaners.

How often should I deep clean my washing machine?

Perform a full deep clean every 1–3 months, depending on usage. Households with hard water, frequent laundry, or softener use should clean more often. Monthly maintenance helps extend intervals between deep cleans.

Why does my washing machine still smell after cleaning?

If odor persists, the issue may be deeper—such as a clogged drain hose, biofilm in the pump, or external plumbing vent problems. Consider professional inspection. Also, ensure you're not using too much detergent, which feeds microbial growth.

Final Steps for Long-Term Freshness

Eliminating mildew from your washing machine isn’t a one-time fix—it’s part of ongoing appliance care. The combination of mechanical cleaning, chemical treatment, and behavioral changes ensures lasting results. By understanding how mildew forms and where it hides, you gain control over your machine’s hygiene.

Modern washing machines are engineered for efficiency, but that efficiency comes with maintenance responsibilities. Just as you wouldn’t skip oil changes in a car, don’t overlook the health of your washer. A clean machine protects your clothes, improves energy efficiency, and prevents costly repairs down the line.

“The best way to avoid a smelly washer is consistency. Five minutes a week can save you hours of deep cleaning later.” — Carlos Mendez, Appliance Technician & Trainer

💬 Take action today: Schedule your deep clean this weekend, mark your calendar for monthly maintenance, and share this guide with someone who’s tired of musty laundry. Your freshest wash starts with a clean machine.