Dishwashers are a necessity for many homeowners‌ — ‌and they’re so affordable and easy to install, ‌they’re often built into new homes or added to old homes.

    However, if a dishwasher has problems, it’s best to diagnose the issue before it worsens‌ — ‌and you end up with a sink full of dirty dishes.

    Read on for some common signs of a clogged dishwasher.

    1. It Smells Funny

    If your dishwasher smells unpleasant when you open the door, this may indicate the plumbing system has a clog with crumbs, grease, and grime. The smell may be slight initially, but it gradually worsens over time.

    Food particles stuck in the drain, filter, or jets can cause a foul odor. Over time, bacteria grow on trapped food debris, creating unpleasant odors.

    Today’s Homeowner Tips

    Run the dishwasher empty on a hot wash cycle with vinegar to help clean the interior and reduce odors. If the smell persists, the clog may be deeper in the plumbing system.

    2. It Makes Unusual Sounds

    When you turn on your dishwasher, listen closely for noises that may signal a clog. Clunking, grinding, or other odd sounds when the dishwasher runs could indicate a blocked drain or jammed pump.

    Food particles or hard objects stuck in the drain can cause unusual sounds as the pump tries to push water through the blockage. Inspect the drain filter, sump, and jets for obstructions. Use a zip tie to secure the spray arms that may be knocking around.

    If noises continue after cleaning, have a technician inspect the dishwasher drain and repair any clogs. A severely jammed impeller may require a pump replacement.

    3. It Operates Irregularly

    A dishwasher that starts and stops repeatedly or shuts off before completing cycles often has a clogged drain. As the pump struggles to drain wash water, activation sensors cause the machine to pause. The dishwasher may also run much longer, trying unsuccessfully to drain.

    Remove any debris caught in the drain filter or sump area. Use a drain cleaner to clear soap scum or food buildup in hoses. For persistent operation issues, the drain likely needs professional cleaning or part replacement to restore normal function.

    4. It Just Doesn’t Clean Your Dishes

    Dishes that consistently come out of the dishwasher dirty or covered in spots are often a sign of clogged wash arms. When spray arms cannot rotate freely, waterjets get blocked, stopping water from reaching dishes.

    Detach the spray arms and use a toothpick to clear any food particles or limescale stuck in the jets. Check the sump and filter for trapped debris, limiting water flow. You may need to replace damaged or warped spray arms for optimal cleaning.

    Getting Professional Help with Stubborn Clogs

    If you’ve tried unclogging your dishwasher yourself to no avail, it’s time to call in a professional. Continuing to run a severely clogged dishwasher can lead to leaks, mold buildup, and damage to the pump. A technician has the tools and expertise to accurately diagnose and fix tricky clogs that DIY efforts cannot resolve. They can clean hoses, remove blockages, and replace parts if needed — saving you time and preventing further issues.

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    So, Is Your Dishwasher Clogged?

    A foul odor, unusual noises, irregular operation, and poor performance are all signs your dishwasher has a clog. Quickly inspect and clean the filter, arms, and sump for obstructions.

    For persistent issues or complex drainage problems, contact a technician to accurately diagnose and fix the clog. Prevent future clogs by running the dishwasher regularly, scraping dishes before loading, and cleaning the filter monthly. Use a dishwasher cleaner monthly to break up grease and limescale.

    FAQs About Clogged Dishwashers

    Where do clogs in a dishwasher come from?

    The most common sources of clogs are food debris, grease, soap scum, and mineral deposits. Small particles can get trapped in the filter, arms, sump, hoses, and pump.

    How can I prevent my dishwasher from getting clogged?

    Run the dishwasher regularly, scrape dishes before loading, and use a dishwasher cleaner monthly to break up grease and limescale.

    What should I do if my dishwasher won't drain at all?

    First, inspect the filter and sump for blockages. Try a drain cleaner made for dishwashers. If it still won’t drain, the clog is likely deeper in the drain line, requiring professional service.

    Why does my dishwasher make a noise when clogged?

    Unusual grinding, knocking, or rattling noises come from debris stuck in the pump or arms. As the pump works harder to push through clogs, it causes components to rattle.

    Editorial Contributors
    avatar for Jonathon Jachura

    Jonathon Jachura


    Jonathon Jachura is a two-time homeowner with hands-on experience with HVAC, gutters, plumbing, lawn care, pest control, and other aspects of owning a home. He is passionate about home maintenance and finding the best services. His main goal is to educate others with crisp, concise descriptions that any homeowner can use. Jon uses his strong technical background to create engaging, easy-to-read, and informative guides. He does most of his home and lawn projects himself but hires professional companies for the “big things.” He knows what goes into finding the best service providers and contractors. Jon studied mechanical engineering at Purdue University in Indiana and worked in the HVAC industry for 12 years. Between his various home improvement projects, he enjoys the outdoors, a good cup of coffee, and spending time with his family.

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    photo of Casey Daniel

    Casey Daniel

    Casey Daniel is a writer and editor with a passion for empowering readers to improve their homes and their lives. She has written and reviewed content across multiple topics, including home improvement, lawn and garden care, sustainability, and health and wellness. When she’s not reviewing articles, Casey is usually playing board games, repainting her bathroom, or quilting.

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