Why does my washing machine smell like sewer and how do I fix it?

Introduction

That unpleasant sewer smell coming from your washing machine is not only embarrassing but can also affect your laundry. This guide will walk you through the most common causes and simple DIY fixes to eliminate the odor for good. Whether you have a top-loader or a front-loader, these steps will help you restore freshness. We'll also cover preventive maintenance so you never have to deal with it again.

Common Causes of Sewer Smell in Washing Machine

1. Clogged or dirty drain pump filter

Over time, lint, coins, and debris collect in the drain pump filter, trapping water and bacteria that produce a foul odor. Check your machine's manual for filter location—usually behind a small access panel at the front bottom. Clean it every 2–3 months for best results.

2. Mould and mildew buildup in the rubber gasket

Front-loading washers are notorious for moisture trapped in the door seal. Wipe the gasket dry after each cycle and leave the door open to air out. For deep cleaning, use a diluted bleach solution or a specialized washing machine cleaner tablet.

3. Standing water in the drum

If your machine doesn't drain completely, water stagnates and becomes a breeding ground for bacteria. Check the drain hose for kinks or clogs. Also verify that the drain standpipe is not blocked.

4. Sewer gas from plumbing vents

If the smell resembles rotten eggs, it might be from the plumbing system itself. A dry P-trap under the sink or a loose connection can let sewer gases escape. Ensure the standpipe is properly vented and that the rubber grommet at the drain hose connection is tight.

Step-by-Step DIY Fix Guide

Step 1: Run a hot water cleaning cycle

Set your washer to the hottest and longest cycle, add 2 cups of white vinegar to the detergent drawer, and run empty. Vinegar cuts through detergent residue and deodorizes. For front-loaders, also pour a cup of vinegar directly into the drum.

Step 2: Deep clean the rubber gasket and door

Using a microfiber cloth and a mixture of equal parts water and vinegar, scrub the rubber seal thoroughly, especially hidden folds. Rinse with clean water and dry completely. If black mould is present, use a soft brush.

Step 3: Clean the detergent drawer and hose

Remove the drawer and soak it in warm soapy water. Use an old toothbrush to clean residue. If the drawer has a biofilm, use diluted bleach. Reinsert when dry.

Step 4: Inspect and clean the drain pump filter

Place a shallow pan under the filter access panel. Unscrew the filter slowly—water will spill. Remove debris, rinse the filter, and reassemble. Dispose of collected lint properly.

Step 5: Flush the drain hose

Disconnect the drain hose from the standpipe or sink and place it in a bucket. Run a short drain cycle to flush out any blockages. If the hose is old or cracked, replace it.

When to Call a Professional

If the smell persists after these steps, the issue could be a clogged vent stack, a malfunctioning drain pump, or a broken pressure switch. In that case, contact a licensed appliance technician.

Preventive Tips to Keep Your Washer Fresh

• Leave the door open after each use for at least an hour.
• Use a washing machine cleaner tablet monthly.
• Clean the rubber gasket weekly with a dry cloth.
• Remove wet laundry promptly.
• Use the right amount of detergent—too much causes buildup.
• Run a monthly hot water cycle with vinegar.

Conclusion

A sewer smell in your washing machine is usually fixable with simple cleaning and maintenance. By following the steps above—especially cleaning the drain filter and running a hot vinegar cycle—you can eliminate odors and extend the life of your appliance. For ongoing care, a dedicated washing machine cleaner helps prevent buildup. If the problem persists, don't hesitate to call a professional. Regular maintenance keeps your laundry fresh and your machine running smoothly.