Bad Smell from Dishwasher? Complete Guide to Eliminating Odors

A bad smell from your dishwasher is not just unpleasant—it can transfer to your "clean" dishes and indicate underlying problems that may worsen over time. Whether you're dealing with a musty, rotten food, sulfur, or sewage-like odor, this comprehensive guide will help you identify the cause and eliminate the smell for good.

At JK Appliances Toronto, we've helped thousands of homeowners across the Greater Toronto Area solve their dishwasher odor problems. Here's everything you need to know about why your dishwasher smells and how to fix it.

Identifying the Type of Smell

Different odors indicate different problems. Let's identify what you're dealing with:

Musty or Mildew Smell

Cause: Trapped moisture and mold growth Location: Usually in the door seal, filter area, or spray arm interiors Severity: Common, easily treatable

Rotten Food or Decay Smell

Cause: Food debris decomposing in the filter, drain, or spray arms Location: Filter, drain sump, food chopper area Severity: Common, requires thorough cleaning

Sulfur or Rotten Egg Smell

Cause: Hydrogen sulfide from bacterial growth Location: Drain hose, garbage disposal connection, standing water Severity: Moderate, may require drain system attention

Sewage or Septic Smell

Cause: Drain line issues, improper installation, or plumbing problems Location: Drain hose, air gap, or plumbing connections Severity: Serious, may require professional attention

Plastic or Burning Smell

Cause: Plastic container melted on heating element, electrical issue Location: Heating element area, electrical components Severity: Urgent, inspect immediately for safety

Solution 1: Deep Clean the Filter System (Most Common Fix)

Why It Matters: The filter is the #1 source of dishwasher odors. It traps food particles that decompose if not cleaned regularly.

Step-by-Step Filter Cleaning:

1. Remove the bottom dish rack for full access

2. Locate and remove the filter

   • Most modern dishwashers have a cylindrical filter in the center
   • Turn counterclockwise to unlock and lift out
   • Remove both the fine filter and coarse filter screen

3. Rinse under hot water

   • Use a soft brush or old toothbrush
   • Scrub all surfaces to remove grease and debris
   • Pay attention to mesh areas

4. Soak in cleaning solution

   • Mix 1 cup white vinegar + 1 cup warm water
   • Soak filters for 20-30 minutes
   • For stubborn odors, add 2 tablespoons baking soda

5. Clean the filter housing

   • With filters removed, use a damp cloth to wipe the sump area
   • Check for food debris in the drain opening
   • Remove any visible objects

6. Reinstall filters securely

   • Ensure filters click into place
   • Never run dishwasher without filters

Recommended Cleaning Frequency:

• Heavy use: Weekly filter cleaning
• Average use: Every 2 weeks
• Light use: Monthly

Solution 2: Clean the Door Seal and Gasket

The Problem: The rubber door seal traps moisture, food particles, and soap residue—creating a perfect environment for mold and mildew.

Door Seal Cleaning Process:

1. Inspect the gasket thoroughly

   • Pull back the rubber folds gently
   • Look for visible mold, mildew, or debris
   • Check both the inner and outer seal surfaces

2. Clean with vinegar solution

   • Mix equal parts white vinegar and warm water
   • Dip a clean cloth or sponge into the solution
   • Wipe all surfaces of the door seal
   • Get into the folds and crevices

3. Address stubborn mold

   • For black mold spots, use a paste of baking soda and water
   • Apply paste, let sit 15 minutes, then scrub
   • For severe cases, use a diluted bleach solution (1:10 ratio)

4. Clean the door edges and hinges

   • Wipe down the door edges
   • Clean around hinges where grime accumulates
   • Don't forget the bottom of the door (often missed!)

5. Dry thoroughly

   • Wipe with a dry cloth
   • Leave door slightly ajar to air dry

Prevention Tips:

• Leave door cracked open after each cycle
• Wipe down gasket monthly
• Check for damaged seals that need replacement

Solution 3: Run a Cleaning Cycle

Why It Works: A proper cleaning cycle removes grease, bacteria, and mineral deposits from interior surfaces.

Method 1: Vinegar Cleaning Cycle

1. Remove all dishes from the dishwasher
2. Place 2 cups of white vinegar in a dishwasher-safe container on the bottom rack
3. Run a hot water cycle (no detergent)
4. The vinegar will deodorize and dissolve grease

Method 2: Baking Soda Follow-Up

1. After the vinegar cycle completes
2. Sprinkle 1 cup of baking soda on the bottom
3. Run a short hot water cycle
4. The baking soda neutralizes remaining odors

Method 3: Commercial Dishwasher Cleaner

Recommended Products:

• Affresh Dishwasher Cleaner - Removes limescale and odors
• Finish Dishwasher Cleaner - Deep cleans grease and grime
• Glisten Dishwasher Magic - Removes rust, limescale, and buildup
• Lemi Shine - Excellent for hard water areas

Usage Instructions:

• Follow package directions
• Run on empty dishwasher
• Use hottest water setting available
• Run monthly for best results

Solution 4: Inspect and Clean the Spray Arms

The Problem: Spray arm holes can become clogged with calcium deposits and food debris, which decompose and create odors.

Spray Arm Cleaning:

1. Remove spray arms

   • Bottom arm: Usually twists or pulls off center mount
   • Middle arm (if present): Snaps onto rack or mount
   • Top arm: May have screw or clips

2. Clear spray holes

   • Hold under running water
   • Use a toothpick or thin wire to clear each hole
   • Check for mineral buildup inside

3. Soak in vinegar

   • Submerge arms in white vinegar for 2 hours
   • This dissolves calcium deposits
   • Rinse thoroughly after soaking

4. Check arm interiors

   • Look inside the arm openings
   • Remove any debris or buildup
   • Ensure water can flow freely

5. Reinstall securely

   • Make sure arms spin freely
   • Test rotation before running cycle

Solution 5: Check the Drain System

Why It Matters: Standing water, clogged drains, and improper hose installation are major odor sources.

Drain Hose Inspection:

1. Check for standing water

   • After a completed cycle, there should be minimal water in the sump
   • More than 1/4 inch indicates a drain problem

2. Verify high loop installation

   • The drain hose should loop up under the counter before descending
   • This prevents backflow from the sink
   • A proper "high loop" is at least 32 inches from the floor

3. Check air gap (if installed)

   • Located on the sink or countertop
   • Remove cap and clean inside
   • Clear any debris from the opening

4. Inspect garbage disposal connection

   • If connected to disposal, run disposal first
   • Check that knockout plug was removed during installation
   • Clear any buildup at the connection

5. Clean the drain hose

   • Disconnect hose (power off first!)
   • Flush with hot water and vinegar
   • Check for clogs or kinks
   • Replace if damaged or heavily soiled

Solution 6: Address Hard Water Issues

The Problem: Mineral deposits from hard water create buildup that traps bacteria and causes odors.

Hard Water Solutions:

1. Use rinse aid

   • Helps water sheet off dishes
   • Reduces mineral spotting
   • Fill dispenser regularly

2. Add citric acid treatments

   • Run empty cycle with 1/4 cup citric acid
   • Dissolves calcium and limescale
   • Safe for all dishwasher components

3. Consider water softener

   • For persistent hard water problems
   • Reduces mineral buildup throughout home

4. Use salt (Miele, Bosch)

   • European brands often have built-in softeners
   • Requires dishwasher salt (not table salt)
   • Follow manufacturer instructions

Solution 7: Proper Loading and Usage Habits

Prevention is Key: Many odor problems start with improper dishwasher use.

Best Practices:

Pre-rinsing:

• Scrape off large food particles
• Don't pre-rinse completely (detergent needs something to work on)
• Never load dishes with bones, fruit pits, or large debris

Loading Tips:

• Don't block spray arms
• Face dirty surfaces toward center
• Don't overload—water needs to circulate

Cycle Selection:

• Use hot water cycles when possible
• Run sanitize cycle weekly
• Avoid eco/quick cycles for heavily soiled loads

Detergent Use:

• Use proper amount (more isn't better)
• Store detergent in cool, dry place
• Use quality detergent appropriate for your water hardness

After Each Cycle:

• Unload promptly
• Leave door slightly ajar
• Wipe down interior monthly

Brand-Specific Odor Solutions

Bosch Dishwashers

Common issues: Water pooling in door gasket, filter drainage Solution: Clean Zeolith (drying) system area; ensure filter seated properly

Samsung Dishwashers

Common issues: Self-cleaning filter generating smells Solution: Run Machine Clean cycle; check waterwall reflector area

LG Dishwashers

Common issues: TrueSteam feature residue Solution: Clean steam vents; run with dishwasher cleaner monthly

Whirlpool/KitchenAid Dishwashers

Common issues: Food chopper area accumulation Solution: Run hot cycle with vinegar; clean chopper area manually

Miele Dishwashers

Common issues: Salt/regeneration system buildup Solution: Check salt level; clean filters and rinse aid dispenser

When the Smell Indicates a Bigger Problem

Call a Professional If:

• Sewage smell persists after cleaning
• You notice water under the dishwasher
• Smell accompanied by poor drainage
• Burning or electrical odors
• Mold growth you can't eliminate

Signs of Plumbing Issues:

• Gurgling sounds during/after cycle
• Water backing up into sink
• Multiple drain fixtures affected
• Persistent sulfur smell

Signs of Component Failure:

• Burning plastic smell (heating element issue)
• Water not draining completely
• Error codes related to drainage
• Standing water that won't clear

Maintenance Schedule for Odor Prevention

Weekly:

• Wipe door gasket
• Check filter for visible debris
• Run hottest cycle with full load

Monthly:

• Deep clean filter
• Run cleaning cycle (vinegar or commercial)
• Clean door seal folds
• Wipe interior surfaces

Quarterly:

• Clean spray arms
• Inspect drain hose
• Check air gap
• Clean exterior controls

Annually:

• Professional inspection
• Check door seal condition
• Verify drain hose installation
• Test heating element

Professional Dishwasher Odor Treatment

When DIY Isn't Enough: Sometimes persistent odors require professional attention.

Our Service Includes:

• Complete disassembly and cleaning
• Drain system inspection
• Component testing
• Seal evaluation
• Installation verification

Service Areas:

• Downtown Toronto
• North York
• Scarborough
• Etobicoke
• Mississauga
• Brampton
• Markham
• Richmond Hill
• Vaughan
• Ajax
• Oakville
• Burlington
• Milton

FAQ: Dishwasher Smell Problems

Q: Why does my dishwasher smell even after cleaning? A: Persistent smells usually indicate issues in hard-to-reach areas like the drain hose interior, air gap, or garbage disposal connection. Try a thorough drain system inspection.

Q: Can I use bleach in my dishwasher? A: Use bleach sparingly and never in stainless steel tub dishwashers. Diluted bleach (1:10) is safe for plastic tubs only. Vinegar is safer for regular use.

Q: How often should I run an empty cleaning cycle? A: Run a cleaning cycle monthly, or every 2 weeks if you use your dishwasher heavily or notice any odor developing.

Q: Why does my dishwasher smell like rotten eggs? A: Sulfur (rotten egg) smell indicates hydrogen sulfide gas, usually from bacterial growth in standing water or the drain system. Clean the drain components thoroughly.

---

Dealing with a smelly dishwasher in Toronto? Contact JK Appliances at +1 647-560-8966 for professional deep cleaning and diagnosis. We service all major dishwasher brands across the Greater Toronto Area!