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Dishwasher Not Cleaning Dishes? 9 Causes and Real Fixes

Published 2026-10-19 · Last reviewed 2026-10-19 · Checked against manufacturer sources

Quick answer

Dirty dishes usually trace back to a clogged filter, spray arm holes plugged with debris, water that isn't hot enough, or loading that blocks the spray. Clean the filter and spray arms, run the kitchen tap hot before starting, and make sure nothing stops the arms from turning. White film is a hard-water issue with its own fix.

Safety first: Switch off the breaker or unplug the dishwasher before removing the filter or spray arms, and wear gloves in case broken glass is caught in the sump. Don't put hand soap or laundry detergent in a dishwasher.

Read the dirt first

What's left on the dishes tells you where to look. Grit and small food bits stuck to glasses point to a clogged filter that's recirculating dirty water. Dirty spots only in one area of a rack suggest a blocked spray arm or something in its way. Greasy film or a detergent pod that didn't fully dissolve can mean the water was too cool. Cloudy white film that won't wipe off is usually mineral from hard water.

Start with the filter and spray arms. They cause more cleaning complaints than anything else, and both are free to fix.

1. Clean the filter

Many current dishwashers have a filter in the tub floor that you're meant to clean by hand, and plenty of owners never find it. Whirlpool recommends cleaning it about once a month, or every two weeks for a big household or daily use, and lists dirty or gritty dishes and odors as the signs. Bosch notes that a clogged filter can put dirt back onto the dishes.

Twist it out, rinse it under the tap and scrub it with a soft brush; wire brushes and scouring pads damage the mesh. Make sure it locks back in. Whirlpool warns against running the dishwasher without its filters properly in place, since that can damage the machine. Our guide on how to clean a dishwasher filter covers the common designs step by step.

2. Clear the spray arm holes

Spin each arm by hand. It should turn freely. Then look at the small holes along the arms: seeds, bits of glass, label paper and limescale plug them, and a blocked hole means a stripe of the rack never gets hit.

Bosch has you unscrew the upper arm and then remove the lower one. Other brands differ, so check the manual for yours. Clear each hole with a toothpick or tweezers, rinse the arm under the tap, shake the water out, and refit it until it clicks or locks. Check the middle arm under the upper rack too, if you have one.

3. Make sure the water is hot enough

Detergent enzymes and grease removal both depend on heat. Whirlpool wants water at about 120°F (49°C) as it enters the dishwasher. If the dishwasher sits far from the water heater, the first fill can be lukewarm water that's been sitting in the pipe. Run the kitchen sink's hot tap until it's hot before you start the cycle. If it never gets properly hot, your water heater may be set too low.

For baked-on food, use a heavier cycle or a high-temperature option. Bosch suggests a program with a higher temperature for stubborn soil. Several brands flag heating faults with a code if the dishwasher can't heat its own water: Whirlpool F4E2 or F4E3, LG HE, Samsung HC or HE, Frigidaire i60, and Bosch E09 (worded a little differently by region).

4. Load so the water can reach everything

Whirlpool says overloading restricts water circulation and leaves dishes dirty. Leave space between items, angle dirty surfaces down and toward the center where the spray comes from, and keep large platters and cutting boards at the sides so they don't shield everything behind them. Put plastics on the top rack.

Before you start, spin the arms once with the racks loaded. A pan handle or a tall utensil hanging through the rack is enough to stop an arm dead. Also make sure nothing blocks the detergent door. Bosch names a tablet that didn't dissolve properly as one of the main reasons dishes stay dirty.

5. Check the detergent

Detergent goes stale once the container has been open a while, especially powder stored under a damp sink. Buy smaller containers, close them tightly and store them somewhere cool and dry. Whirlpool says good-quality pre-measured packs or tablets reduce film better than loose powder or gel.

Never use hand dish soap. It fills the tub with suds, which stop the wash and can leak out the door. Whirlpool and KitchenAid flag that as F6E3, and LG as bE.

6. Hard water film and rinse aid

If glasses come out cloudy and the film doesn't wipe off with a damp cloth, it's mineral. Fill the rinse aid dispenser and keep it full; it helps water sheet off and limits spotting. Whirlpool says very hard water (15 grains per gallon or more) can damage the dishwasher, recommends a water softener, and suggests a dishwasher cleaner or a white vinegar rinse to remove white spots and film.

7. Check the water supply

A dishwasher that doesn't get enough water can't clean. Make sure the supply valve under the sink is fully open; Whirlpool lists a partly closed valve as a cause. Low fill codes include LG IE, Samsung 4C or 4E, Frigidaire i10 and Whirlpool F8E1 or H2O.

8. When it's a part

If the filter and arms are clean, the water is hot and the loading is good, the problem may be mechanical. A weak wash pump moves too little water, and a failed diverter can stop water going to one of the arms (Whirlpool and KitchenAid show FAE4 or F10E4 for that, and LG shows nE on models with a vario spray system). A wash motor fault shows as F7E2 on Whirlpool and KitchenAid and as LE (CE on some models) on LG. Pump, diverter and motor repairs mean taking the sump apart, and they're work for a technician. One exception: on Samsung models with the Waterwall system, 7E or 7C means the reflector that slides along the back of the tub can't move, and the cause is often just a dish or utensil in its path or a reflector that isn't seated right.

When to call a professional

Book a technician if clean filters, clear arms, hot water and proper loading don't fix it, or if you hear the motor running but little or no spraying. Any wash motor, heating or diverter code that returns after a reset needs a repair visit.

Parts involved

Error codes for this problem

Sources we checked