Your washing machine cleans your clothes, but who’s cleaning your washing machine? If you can’t remember the last time you gave it a proper scrub, that funky smell wafting from your laundry room might be your answer.

Don’t panic and start shopping for a new washer just yet. A thorough clean can sort most odour problems and get your machine running like new again.

Why does my washing machine smell bad?

Washing machine smells are typically caused by bacteria, mould, and detergent buildup trapped in damp areas of the machine.

smelly washing machine

Low-temperature wash cycles: Modern energy-efficient washing increasingly relies on 30°C or cold washes, which save energy but don’t kill bacteria or dissolve detergent residue effectively. Bacteria thrive at these temperatures, multiplying in damp areas and producing unpleasant odours. Detergent and fabric softener residues that would dissolve in hot water instead accumulate at low temperatures, creating sticky films where bacteria colonize.

Excess detergent use: Using too much detergent—a common mistake—creates excessive suds that don’t rinse away completely. Residual detergent deposits in the drum, door seal folds, detergent drawer, and internal pipes. This organic material feeds bacteria and mould, accelerating odour development. Modern concentrated detergents require far less product than many people use, yet packaging recommendations often err toward excess to sell more product.

Trapped moisture: Front-loading washing machines seal completely during operation, and many users close the door immediately after cycles complete. Without air circulation, moisture remains trapped inside the drum and particularly in the rubber door seal’s folds. This constant dampness provides perfect conditions for mould and bacteria growth. The warm, moist, dark environment inside a closed washing machine is essentially an incubator for odour-causing microorganisms.

Poor ventilation: Washing machines installed in confined spaces—tight kitchen cupboards, enclosed utility rooms without ventilation, or bathroom cabinets—suffer worse odour problems because ambient moisture cannot dissipate. The machine’s exterior may feel damp to touch, and visible condensation might form on surfaces, indicating inadequate ventilation encouraging internal moisture retention and biological growth.

Why does my washing machine smell like sewage?

A sewage smell often indicates a blocked drain hose, dirty filter, or plumbing trap issue.

broken washing machine

Drain hose positioning: If your drain hose sits too low in the standpipe or waste connection, sewer gases can travel backward through the hose into the machine. The drain hose should enter the standpipe at least 600mm above floor level with an air gap around it preventing direct contact with wastewater in the pipe. Incorrectly positioned hoses create a direct pathway for sewer odours.
Standpipe issues: The standpipe trap (U-bend) should maintain a water seal preventing sewer gas entry. If this trap dries out from infrequent machine use, evaporation breaks the seal allowing gases to escape. This is common in rental properties between tenancies or holiday homes used seasonally. Additionally, blocked standpipes can cause wastewater backing up, creating sewage smells around the washing machine area.
Waste trap problems: In installations where washing machines drain into sink waste systems rather than dedicated standpipes, inadequate traps or improperly vented drainage can allow sewer gas to permeate through the system. Combined waste systems serving multiple appliances are particularly vulnerable if venting is inadequate or blockages restrict airflow.
When plumbing inspection is needed: Persistent sewage smells despite cleaning the machine itself indicate drainage system problems requiring professional plumbing inspection. This might reveal blocked waste pipes, failed trap seals, inadequate venting, or installation errors. Sewer gas contains methane and hydrogen sulfide—both hazardous at high concentrations—making proper diagnosis and repair essential for health and safety beyond just eliminating unpleasant odours.

Why does my washing machine smell like rotten eggs?

A rotten egg smell usually comes from bacteria growth inside the drum seal or drainage system.

The characteristic rotten egg odour is hydrogen sulfide gas produced by anaerobic bacteria (bacteria thriving without oxygen) breaking down organic matter. These bacteria colonize areas where water sits stagnant and oxygen is limited—perfect conditions exist in washing machine door seals, drain hoses, and pump cavities.

Biofilm buildup: Bacteria don’t exist individually but form biofilms—slimy communities of microorganisms embedded in a protective matrix. These biofilms develop on all surfaces inside your washing machine where moisture and nutrients (detergent residue, fabric fibres, body oils transferred from clothes) are present. The biofilm protects bacteria from brief exposure to detergents during wash cycles, allowing colonies to persist and produce foul-smelling metabolic byproducts.

Rubber door seal contamination: The rubber door seal’s folds trap water, lint, detergent residue, and debris after each wash. Without regular cleaning and drying, this becomes an ideal bacterial habitat. The accordion folds in door seals are particularly problematic—water pooling in the lowest fold never fully evaporates, maintaining constant moisture supporting bacterial growth. Running your fingers along these folds often reveals slimy black residue—this is biofilm containing the bacteria producing rotten egg odours.

Internal pipe residue: The drain hose’s interior, pump housing, and internal drainage pipes accumulate organic residue over time. Standing water in the pump cavity between washes provides another bacterial habitat. These internal areas are invisible during normal operation but significantly contribute to whole-machine odour. When the machine drains, foul-smelling water from these contaminated areas flows through the drum, transferring odours to subsequent laundry loads.

How do you clean a smelly washing machine?

Run a hot maintenance wash with a washing machine cleaner or white vinegar and baking soda to remove residue and bacteria.

Step-by-step cleaning method:

Empty the drum completely removing all laundry
Add cleaning agent to the detergent drawer or directly into the drum:
- Commercial washing machine cleaner (follow packet instructions), OR
- 250ml white vinegar in the detergent drawer plus 2 tablespoons baking soda directly in the drum
Select the hottest, longest wash cycle available (typically 90°C or 95°C if your machine offers it)
Run the complete cycle without interruption
Run a second rinse cycle ensuring all cleaning residue is removed

Cleaning the detergent drawer:

Remove the detergent drawer completely (usually by pulling fully out then pressing a release tab). Wash thoroughly in hot water with washing-up liquid, using an old toothbrush to scrub compartments where residue accumulates. Pay particular attention to the fabric softener compartment which often has slimy buildup. Rinse thoroughly and dry before replacing.

Wiping the rubber seal:

Pull back the rubber door seal folds exposing all surfaces. Using a cloth dampened with diluted white vinegar (1 part vinegar to 1 part water) or a commercial mould remover, wipe thoroughly around the entire seal circumference. Ensure you reach into all folds—there are usually multiple layers. Remove any visible debris, black mould spots, or slimy residue. Dry completely with a clean towel.

Cleaning the drum:

After the maintenance wash completes, wipe the drum interior with a clean cloth dampened with diluted vinegar. Check around the drum holes (where water enters and exits) for residue buildup. These areas can trap debris and harbour bacteria. Wipe thoroughly and leave the door open allowing the drum to air dry completely.

This deep cleaning should be performed monthly in hard water areas or heavy-use households, every 2-3 months for typical use.

How do you clean the washing machine filter?

Turn off the machine, open the lower access panel, drain excess water, and remove debris from the filter housing.

Safety precautions:

Always unplug the washing machine before accessing the filter—this prevents accidental cycle starts and eliminates electrical shock risks. Place old towels on the floor beneath the access panel as residual water will spill when you open the filter. Have a shallow container (old takeaway container works well) ready to catch water.

Filter cleaning procedure:

Locate the filter access panel at the machine’s front bottom (usually lower right)
Open the panel by pulling the tab or releasing clips
Place towels and container to catch water spillage
Slowly unscrew the filter cap anticlockwise while supporting it—water will begin draining
Allow water to drain into your container, pausing if it fills
Remove the filter completely once drainage slows
Clear all debris from the filter and housing cavity—common blockages include coins, buttons, hairpins, lint, and small clothing items
Rinse the filter thoroughly under running water
Check the filter housing for additional debris or objects
Replace the filter ensuring it screws in firmly and seals properly
Close the access panel securely
Run a test rinse cycle checking for leaks around the filter

Common blockages:

Filters catch items that pass through drum holes but are too large for the pump—coins, buttons, bra underwires, hairgrips, tissues (which create papier-mâché-like masses), lint accumulation, and small socks. These obstructions prevent proper drainage and create stagnant water perfect for bacterial growth and odour development.

How often to clean:

Check and clean the filter monthly as preventative maintenance. More frequent cleaning (every 2 weeks) benefits households washing heavily soiled clothes, properties with hard water, or machines processing laundry for multiple people. Regular filter maintenance prevents drainage problems, reduces odours, and extends pump lifespan by preventing debris reaching pump impellers.

How do you remove mould from the washing machine seal?

Wipe the rubber seal with diluted white vinegar or a mould-removal solution and dry thoroughly.

Detailed cleaning process:

Prepare cleaning solution: Mix equal parts white vinegar and water in a spray bottle, OR use a commercial mould remover suitable for rubber
Pull back seal folds exposing all surfaces including the innermost fold
Spray liberally on all visible mould spots and affected areas
Leave for 10-15 minutes allowing the solution to penetrate and kill mould
Scrub with an old toothbrush paying attention to heavily affected areas and textured seal surfaces where mould embeds
Wipe clean with a damp cloth removing dead mould and cleaning residue
Dry thoroughly with a clean towel ensuring all moisture is removed from folds
Leave door open for several hours allowing complete drying

Pulling back the seal folds:

Door seals typically have multiple accordion-style folds. Don’t just wipe the visible surface—you must pull the seal away from the door opening to access hidden folds where mould primarily grows. The bottom fold is usually worst affected as water and debris naturally settle there. Be thorough but gentle to avoid damaging the seal.

Preventing regrowth:

Mould returns if conditions remain favourable. After every wash, wipe the seal dry with a towel and leave the door open allowing air circulation. This simple habit prevents the constant dampness mould requires for growth. Monthly maintenance washes with hot water and vinegar help prevent mould establishing itself.

Avoiding harsh chemical damage:

Bleach is effective against mould but can degrade rubber seals over time, causing them to perish, crack, or lose elasticity. If using bleach-based products, dilute appropriately and limit frequency. Rinse thoroughly after use. Repeated harsh chemical exposure shortens seal lifespan, eventually requiring expensive seal replacement. Vinegar is gentler while remaining effective for regular maintenance.

Does vinegar damage a washing machine?

Occasional use of diluted white vinegar is generally safe, but excessive use may affect rubber seals over time.

Safe frequency:

Using vinegar for monthly maintenance washes is considered safe by most appliance manufacturers. The acidity in white vinegar (approximately 5% acetic acid) effectively dissolves mineral deposits, breaks down detergent residue, and kills bacteria without the harsh effects of stronger chemicals. However, using vinegar weekly or in every wash may accelerate rubber seal degradation over years.

Alternative commercial cleaners:

Purpose-designed washing machine cleaners contain balanced formulations specifically developed for appliance cleaning. These products clean effectively while incorporating ingredients protecting rubber and plastic components from degradation. Brands like Dr. Beckmann, Dettol, and Calgon offer washing machine cleaners widely available across UK supermarkets. Follow packet instructions for correct dosing and frequency.

Descaling products:

In hard water areas across London and much of the UK, limescale accumulation in heating elements, pipes, and pumps reduces efficiency and can cause mechanical failures. Descaling products specifically target mineral deposits. Use these every 3-6 months in hard water areas, more frequently if you notice white chalky deposits on heating elements (visible in some machines) or if your kettle scales rapidly.

The key is balance—occasional vinegar use or commercial cleaning products maintain your machine effectively without causing damage. Daily vinegar use would be excessive; monthly use is appropriate.

How often should you clean your washing machine?

Run a hot maintenance wash once a month to prevent odours and buildup.

Heavy-use households:

Families running multiple wash loads daily, households washing sports clothing regularly, or properties washing work uniforms or pet bedding should increase maintenance frequency to every 2-3 weeks. Heavy use means more detergent, fabric softener, and organic material passing through the machine, accelerating residue buildup and bacterial growth.

Hard water areas:

London boroughs in the East and North typically have harder water than those in the West and South. Hard water creates limescale deposits on heating elements and internal pipework, reducing efficiency and creating rough surfaces where bacteria colonize more readily. Properties in hard water areas benefit from monthly descaling maintenance in addition to standard cleaning cycles.

Landlord maintenance advice:

Landlords providing washing machines should ensure tenants understand basic maintenance requirements. Include simple maintenance instructions in welcome packs: monthly maintenance washes, leaving the door open after use, and filter cleaning. Schedule professional appliance servicing annually as part of property maintenance programs. Well-maintained machines last longer, require fewer emergency repairs, and maintain tenant satisfaction—all reducing landlord costs long-term.

Consistent monthly maintenance takes 2-3 hours (mostly machine running time) and prevents the deep cleaning or professional intervention required when machines develop serious odour or performance problems from neglect.

Why does my washing machine still smell after cleaning?

Persistent smells may indicate a hidden blockage, internal drain buildup, or plumbing issue.

Hidden pump debris:

The drain pump itself, beyond the accessible filter, can harbor debris. Small items occasionally bypass the filter or fragments break down from larger blockages. Accessing the pump for cleaning requires partial machine disassembly—removing panels, disconnecting hoses, and potentially removing the pump unit. This is beyond typical DIY scope and requires professional appliance engineer intervention.

Drain hose contamination:

The internal surface of drain hoses accumulates biofilm, lint, and detergent residue over years. This contamination layer continues producing odours despite cleaning accessible machine parts. Drain hose replacement is relatively straightforward for professionals but requires accessing connections at both the machine and standpipe ends. New hoses cost £10-20, with labor adding to the total cost if professionally installed.

Sewer gas backflow:

If smells persist despite thorough machine cleaning, sewer gas entering through the drainage system is likely. This indicates plumbing rather than appliance problems. Check the standpipe trap has adequate water seal (pour a bucket of water down if the machine is used infrequently). Verify the drain hose positioning maintains appropriate height and air gap. Persistent sewer odours require professional plumbing inspection to identify venting issues, blocked waste pipes, or trap failures.

When professional inspection is needed:

If you’ve completed thorough cleaning including drum, seal, filter, and detergent drawer, run multiple hot maintenance washes, and smells persist or return within days, professional diagnosis is appropriate. The problem might be:

Failed bearings allowing water behind the drum where it stagnates
Damaged internal hoses leaking water into areas that cannot drain properly
Pump cavity corrosion or damage creating bacterial habitats
Control system faults preventing proper drainage
Installation problems with drainage plumbing

These issues require specialist diagnosis and repair beyond DIY capabilities.

How can you prevent washing machine smells?

Leave the door open after use, avoid excess detergent, and run regular hot washes to prevent bacterial growth.

Air circulation:

Immediately after each wash cycle completes, open the door fully and pull out the detergent drawer. Leave both open for several hours or until the drum and seal are completely dry. This simple habit is the single most effective odour prevention measure. Air circulation allows moisture to evaporate rather than creating stagnant damp conditions bacteria require. If possible, position the machine in a well-ventilated area rather than enclosed cupboards.

Correct detergent dosing:

Use significantly less detergent than you probably think necessary. Modern concentrated formulas are extremely effective—for soft to moderately hard water, 1-2 tablespoons of liquid or 1 tablespoon of powder suffices for normal loads. Check your water hardness on your water supplier’s website and follow detergent manufacturer’s recommendations for your specific hardness level. Excess detergent doesn’t improve cleaning—it creates residue feeding bacteria and wasting money.

Avoiding constant cold washes:

While cold washing saves energy, bacteria thrive at low temperatures. Run at least one 60°C or hotter wash weekly. This doesn’t need to be a full load—half-load programs work fine. The hot water and longer exposure kills bacteria, dissolves residue, and maintains machine hygiene. Towels and bedding are ideal candidates for regular hot washes as they benefit from higher temperatures for hygiene reasons anyway.

Checking pockets for debris:

Tissues, coins, wrappers, and organic matter from pockets contribute to filter blockages and provide food for bacterial growth. Make pocket-checking part of your laundry routine before loading the machine. This prevents debris accumulation, protects clothes (tissue shreds create lint on everything), and reduces filter cleaning frequency.

Additional preventative measures:

Use quality detergents formulated for modern machines
Avoid fabric softener overuse—it creates sticky residue
Don’t leave wet laundry in the drum after cycles complete
Wipe the seal dry after each wash in heavy-use households
Run empty hot washes monthly even if you regularly wash hot loads

When should you call a professional?

If odours persist despite deep cleaning, or if there are drainage or plumbing concerns, a qualified engineer should inspect the appliance.

Recurring smells: Smells returning within days despite thorough cleaning indicate underlying problems beyond normal maintenance scope. This suggests internal contamination, component failures, or installation issues requiring specialist diagnosis. Don’t repeatedly purchase cleaning products attempting to mask symptoms—address the root cause through professional inspection.
Standing water: Water remaining in the drum between washes (visible when you open the door days after the last wash) indicates drainage system failures. This might stem from blocked pumps, failed pump motors, control system faults preventing complete drainage, or plumbing blockages. Standing water creates perfect bacterial breeding conditions making odour elimination impossible without resolving the drainage fault.
Suspected pump or drain failure: If your machine displays drainage error codes, takes excessively long to drain, or makes unusual noises during drain cycles alongside persistent odours, pump or drainage system components have likely failed. These mechanical and electrical failures require professional repair with genuine replacement parts ensuring reliable operation.
Plumbing concerns: Persistent sewage smells, visible wastewater backing up from standpipes, gurgling from drains during machine operation, or damp patches near waste pipe connections indicate plumbing problems beyond the appliance itself. These require professional plumbing assessment addressing waste pipe blockages, venting inadequacies, or trap failures.

For appliance repairs, maintenance, and professional odour diagnosis across London, qualified engineers identify whether odours stem from cleaning neglect, component failures, or installation problems, providing targeted solutions restoring fresh-smelling, properly-functioning washing machines.

How To Rid Smell From Washing Machine