Dishwasher Not Cleaning Properly? Causes & Fixes

1. Give water a clear path through the load

Separate nested bowls and utensils, face soiled surfaces toward the spray and keep tall items away from spray arms and the detergent dispenser. Check that racks are seated and an accessible arm can move freely, following the manual. Scrape off large food scraps. If only one rack washes poorly, record which one; a blocked arm or rack water connection can affect that area without explaining every possible cleaning fault.

2. Clean filters and inspect spray openings

A dirty filter can retain debris, and blocked spray openings can restrict where wash water reaches. Clean an owner-removable filter and inspect accessible arms according to the model's instructions. Do not enlarge holes, force fittings or remove parts the manual reserves for service. Refit filters and arms correctly. If a part is cracked or will not seat properly, record it for the technician rather than improvising a repair.

3. Match detergent and the cycle to the load

Use fresh automatic dishwasher detergent and the recommended amount. Hand dish soap creates foam and is unsuitable. Make sure a dish is not blocking the dispenser and select a cycle appropriate for the soil level; a short rinse is not a full wash. Film or spotting may involve water hardness, detergent or rinse-aid settings rather than the same cause as food left on plates. Follow the manufacturer's guidance for your water conditions.

4. Consider water temperature and supply

Consult the manual for the required incoming water temperature and supply conditions rather than applying a single setting to every model. If filling seems different from normal or the cycle stops with a water-related code, note that change. Do not force a stiff shut-off valve, disconnect the inlet line or alter the household heater as a diagnostic shortcut. Restricted supply or an inlet-valve fault requires assessment.

5. Know when circulation or heating needs testing

A dishwasher that fills but does not circulate water normally may have a wash-pump, motor, water-path or control fault. Poor cleaning combined with an interrupted cycle or heating-related error can also require heating-circuit or sensor checks. Noise or cold dishes alone cannot identify a failed component. A technician needs to distinguish a maintenance issue from a mechanical or electrical fault before recommending parts.

When professional diagnosis is appropriate

Book diagnosis when cleaning remains poor after the model's loading and maintenance checks, spray action appears absent, a rack repeatedly fails to wash, or an error code returns. Note whether draining and drying also changed. Recurring faults, unusual grinding, an interrupted cycle or a leak warrant service rather than repeated detergent changes or resets.

For an appliance fault, learn about our dishwasher repair service, including diagnosis, documented work and booking options in Toronto and the GTA.

What to share when requesting service

Share the model, affected rack, type of residue, selected cycle and detergent. Mention whether the appliance fills, circulates, drains and finishes the cycle, and photograph any displayed code.

Related guidance

• Dishwasher Not Draining? Causes & What to Check
• Dishwasher Leaking? Common Causes & What to Check