If your washing machine smells like sewage, the cause is usually a buildup of bacteria, blocked drainage components, or trapped water rather than a plumbing system failure.
Unpleasant smells are common when moisture and residue collect inside the machine.
The Most Common Reasons This Happens
1. Dirty Drum or Detergent Residue
Over time, detergent and fabric softener can build up inside the drum and seals. This creates an environment where bacteria grow and produce odours.
Running regular maintenance cycles helps prevent this.
2. Blocked Pump Filter
If debris collects in the filter, stagnant water can produce a sewage-like smell.
If your machine also drains slowly, see:
→ Why Is My Washing Machine Not Draining?
3. Drain Hose Issue
If the drain hose is kinked, partially blocked, or incorrectly installed, wastewater may not flow properly, leading to odours.
If other drains in your home smell, see:
→ Plumbing Problems Explained
4. Mold in Door Seal
Front-loading machines are especially prone to mold buildup in the rubber door seal.
Check for trapped moisture or residue.
5. Low Temperature Washes Only
Frequent cold washes can allow bacteria to accumulate inside the machine.
Running a hotter maintenance wash periodically may help.
Is This Normal?
It may be minor if:
- The machine hasn’t been cleaned recently
- The smell disappears after a hot cycle
- The filter hasn’t been inspected
It may require attention if:
- The smell persists after cleaning
- Water remains in the drum
- Other drains also smell
What You Can Do
If your washing machine smells like sewage, you can:
- Clean the drum and door seal
- Check and clean the pump filter
- Inspect the drain hose
- Run a hot maintenance wash
If odours continue despite cleaning, further inspection may be needed.
For more related issues, see:
→ Washing Machine Problems Explained
→ Appliance Problems Explained