Why is my dishwasher not cleaning the dishes?
A dishwasher that stops cleaning well is almost always a clogged filter screen or blocked spray arm — a free DIY fix that takes about 10 minutes. If cleaning the filter doesn't help, the next likely cause is low water temperature or a failing wash motor, which runs $150 – $350 repaired.
Dishwasher cleaning problems almost never require a new machine — the filter and spray arms are maintenance items that most homeowners don't know exist. Clean them first. If the problem persists, a tech can diagnose the water heater, pump, or detergent dispenser quickly.
Most likely causes
| Cause | How to tell | The fix | Typical cost |
|---|---|---|---|
| Clogged filter screen | Dishes coming out cloudy or gritty; standing water or debris in the bottom of the tub after a cycle; problem got worse gradually | Remove and rinse the filter under running water — it's usually a twist-lock assembly in the floor of the tub. Do this monthly. | $0 |
| Blocked or clogged spray arms | Dishes on a specific rack (top or bottom) consistently come out dirty while the other rack looks fine; spray arm doesn't spin freely by hand | Remove the spray arms and clear the holes with a toothpick or small wire; rinse under running water | $0 |
| Water not hot enough | Dishes feel slightly warm but not hot after a cycle; greasy residue remains; dishwasher runs full cycle but doesn't clean effectively | Check your water heater — most dishwashers need incoming water at 120°F minimum. Run the hot tap at the kitchen sink until it's truly hot before starting a cycle. | $0 – $150 (if water heater adjustment needed) |
| Detergent dispenser not opening | Detergent pod or powder found intact in the dispenser after the cycle ends; dishes look completely unwashed | Replace the detergent dispenser door latch or actuator | $100 – $200 |
| Wash pump motor weak or failing | Dishes come out dirty even after filter and spray arms are cleaned; water pressure inside the tub sounds low during cycle | Replace the wash pump motor | $150 – $350 |
Try this first (before you pay anyone)
- Find and clean the filter. In most dishwashers, it's a round twist-lock cylinder in the bottom of the tub floor — turn it counterclockwise, lift out, and rinse under running water. If it's packed with food debris, you found your problem.
- Remove the spray arms (usually just unscrew or pull straight up) and hold them up to the light. If the small holes are clogged with hard water deposits or food, clear them with a toothpick and rinse well.
- Run your kitchen hot water tap until it's steaming hot before starting the dishwasher. This pre-heats the line so the dishwasher fills with already-hot water instead of waiting for cold water to heat up in the appliance.
- Check the inside of the door for the detergent dispenser. Did the pod or powder actually get used? If you find it dry and intact after the cycle, the dispenser door failed to open.
Call a pro when…
- Cleaning the filter and spray arms doesn't improve results after 2–3 cycles — the pump, water inlet valve, or dispenser likely needs attention
- The dispenser door looks broken or snapped — the latch actuator needs replacement
- There's standing water left in the tub after cycles — a drain pump issue that's causing both the cleaning and drainage problems
- You hear unusual grinding or loud humming during the wash cycle — a pump bearing or wash motor is failing
Repair or replace?
Dishwashers typically last 9–10 years. A detergent dispenser, spray arm replacement, or pump repair on a dishwasher under 7 years old is worth doing — you're spending $100–$350 on an appliance that costs $500–$1,200 new. Past 8–9 years, or if the repair quote exceeds half the cost of a comparable replacement, a new unit is usually the smarter buy. Modern dishwashers are also significantly more water-efficient than models from 10+ years ago, so replacement often lowers utility costs too.
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Related questions
Why are my dishes coming out of the dishwasher still dirty?
The most common cause by far is a clogged filter in the bottom of the tub — most homeowners don't know it exists and it can go years without cleaning. Second most common: blocked spray arm holes that can't rotate or spray properly. Both take under 10 minutes to fix and cost nothing.
How much does it cost to repair a dishwasher that won't clean?
If it's the filter or spray arms, it's free — just clean them. If a part needs replacing (detergent dispenser, pump, water inlet valve), expect $100–$350 including parts and labor. The diagnostic visit runs $75–$150 and is usually credited toward the repair.
Does the type of detergent matter for cleaning performance?
Yes — dishwasher pods outperform loose powder in most modern machines because they dissolve reliably at specific cycle points. Using too much or too little detergent also affects results. If you recently switched detergent brands and performance dropped, try switching back or using a pod.
Why does my dishwasher leave white residue on glasses?
White film on glasses is almost always hard water deposits, not a cleaning failure. It won't go away with more detergent — you need a rinse aid (fills in the dispenser on the door) and periodic cleaning with a dishwasher cleaner tablet or citric acid powder. A plumber can also assess a whole-home water softener if your water is very hard.