Opening your machine only to ask why is my dishwasher not cleaning is a major frustration. While it may seem like the motor is failing, poor performance is frequently tied to restricted water flow or temperature issues that you can fix yourself. This guide ranks solutions from most likely to least likely to help you diagnose the issue efficiently.
5 Common Causes for Dishwasher Not Cleaning
1Clogged Spray Arms
The spray arms are the rotating plastic or metal bars that shoot water at your dishes. Over time, calcium deposits (hard water) or small seeds and glass shards can plug the tiny nozzles, resulting in “dead zones” where dishes remain dirty.
Symptoms
- Dishes in specific corners of the racks remain unwashed.
- You can hear water splashing, but it sounds “weak” or uneven.
Care Plan
- Remove the bottom rack and unscrew or pop off the spray arms.
- Inspect each tiny hole for visible debris or white mineral scale.
- Use a toothpick or a bent paperclip to gently clear each nozzle.
- Rinse the arms under a faucet to ensure water flows freely through all ports.
- Snap the arms back into place and ensure they spin freely without hitting the racks.
Common Mistakes
- Using a toothpick that breaks off inside the nozzle, making the clog worse.
- Forgetting to check the top spray arm or the small “middle” arm attached to the upper rack.
2Dirty or Saturated Filter
Your dishwasher’s filter prevents food particles from being recirculated onto “clean” dishes. If the filter is full of grease or “gunk,” the machine will essentially wash your plates with dirty, gritty water.
Symptoms
- Dishes feel “gritty” or have a sandy residue after the cycle.
- A foul odor lingers inside the tub even when empty.
Care Plan
- Remove the bottom rack to access the filter assembly in the floor of the tub.
- Twist and lift out the cylindrical fine-mesh filter.
- Scrub the filter with warm water and a soft brush (a toothbrush works best).
- Inspect the area under the filter for any trapped food chunks or debris.
- Reinstall the filter firmly; if it’s loose, debris will bypass it and clog your spray arms (Cause 1).
Common Mistakes
- Using a wire brush, which can puncture the delicate mesh filter.
- Thinking the dishwasher is “self-cleaning” and never checking the filter.
3Failed Water Inlet Valve
The water inlet valve controls how much water enters the machine. If this valve is partially restricted by sediment or failing electrically, the dishwasher won’t fill with enough water to create the pressure needed for cleaning.
Symptoms
- The water level at the bottom of the tub is low (it should normally reach the heating element).
- The machine makes a “humming” or “buzzing” sound during the fill cycle.
Care Plan
- Access the valve (usually behind the bottom kickplate).
- Inspect the small screen filter where the water line connects; clean out any rust or sand.
- Use a multimeter to test the valve solenoid for continuity.
- If the valve is clogged or has no continuity, replace it with a new 2026-spec part.
- Ensure the water supply line is fully open and not kinked.
Common Mistakes
- Replacing the circulation pump when the machine simply wasn’t getting enough water to begin with.
4Broken Detergent Dispenser
If the detergent dispenser door doesn’t open at the right time (or at all), the soap won’t mix with the water during the main wash cycle. Alternatively, if the door is blocked by a tall plate, the tablet will only partially dissolve.
Symptoms
- The detergent tablet is still in the dispenser or lying on the floor of the tub at the end of the cycle.
- The dishes look rinsed but still have grease on them.
Care Plan
- Check the dispenser door for any dried soap residue that might be “gluing” it shut.
- Ensure you aren’t loading tall cookie sheets or plates directly in front of the dispenser.
- Inspect the spring and latch on the dispenser door for damage.
- Test the dispenser solenoid with a multimeter if the door refuses to open during a cycle.
- If the latch is broken, replace the entire dispenser assembly.
Common Mistakes
- Using “wet” hands to handle detergent pods, which causes the pod to stick to the dispenser wall.
5Faulty Heating Element
Dishwasher detergent is designed to work in water that is 120°F to 150°F. If the heating element is burnt out, the water stays cold, grease won’t dissolve, and the detergent won’t activate.
Symptoms
- Dishes are soaking wet and cold at the end of the cycle.
- The “Sanitize” or “High Temp” light is blinking an error code.
Care Plan
- Before starting cycles, run the kitchen hot-water tap until it is fully hot so the dishwasher fills with hot water from minute one.
- Unplug the dishwasher and look at the large “hoop” element at the bottom of the tub.
- If you see visible cracks, blisters, or white “burn” marks, the element is dead.
- Test the element for continuity using a multimeter at the terminals under the machine.
- If there is no continuity, replace the element.
- Check the high-limit thermostat (hi-limit) if the element is fine; it may have tripped.
Common Mistakes
- Assuming the “Dry” cycle is the only time the heater works; it is essential for the “Wash” cycle too.
