Troubleshooting guide
Dishwasher Not Cleaning Dishes? Here's Why
- ✓ $79 diagnostic, credited to the repair
- ✓ 45-day parts & labor warranty
- ✓ Same-day & next-day visits
- ✓ 6+ years repair experience
Quick answer
A dishwasher that leaves food behind usually has a dirty filter, clogged spray arm holes, or water that isn't hot enough. Clean the filter, clear the spray arms and run the kitchen tap until it's hot before you start. If that doesn't help, a weak wash pump, a failing water inlet valve or a dead heating element may be the cause.
A dishwasher cleans with three things: hot water, detergent and pressure. When dishes come out dirty, one of those is missing. The trick is finding which one, and the cheapest causes are by far the most common.
Before you blame the machine, look at the pattern. Grit on everything points to the filter. Dirty dishes on just one rack points to that rack's spray arm. A cloudy film is usually a water or detergent issue, which we cover in a separate guide on cloudy glasses.
Causes, from most to least likely
1.Dirty filter
Modern dishwashers recirculate the same water through the cycle. If the filter is packed with food, that dirty water gets sprayed back onto your dishes. A clogged filter also starves the wash pump of water, so pressure drops.
- Check it yourself
- Remove the bottom rack, twist out the cylindrical filter and lift out the flat mesh. Scrub both with warm soapy water and a soft brush. Reinstall until it locks.
- The fix
- Most of the time, cleaning the filter is the whole fix. We show customers where it is and how often to clean it so the problem doesn't come back.
2.Clogged or blocked spray arms
Spray arms have small holes that clog with seeds, bits of label, glass and mineral scale. A tall pan or utensil hanging through the rack can also stop an arm from spinning. A spray arm that doesn't spin cleans only a narrow strip.
- Check it yourself
- Spin each arm by hand — it should turn freely without hitting anything. Remove the arms (most unscrew or unclip; check your manual), rinse them and clear the holes with a toothpick. Shake each arm and listen for loose debris inside.
- The fix
- A cracked arm or a broken mounting hub is replaced. Arms are inexpensive parts and usually fixed in one visit.
3.Water not hot enough
Detergent enzymes and grease removal both depend on heat. Many dishwashers fill from the kitchen hot line. If the first gallon or two is cold water that has been sitting in the pipe, the wash starts cold. A water heater turned down low makes it worse.
- Check it yourself
- Run the kitchen tap until it's hot, then start the dishwasher. Choose a normal or heavy cycle rather than an eco or quick cycle for dirty loads. Check that the water heater is set around 120°F.
- The fix
- If the water is hot at the sink but the dishwasher still runs cool, the dishwasher's own heater may not be working (see below).
4.Loading and detergent
Large items in front of the detergent dispenser block it from opening fully. Bowls nested together or facing the wrong way shield each other. Old powdered detergent clumps and doesn't dissolve, especially in a humid Florida kitchen.
- Check it yourself
- Make sure nothing blocks the detergent door or the spray arms. Face dirty surfaces toward the center. Use fresh detergent stored in a dry, sealed container. Check that the dispenser door opens and the detergent is gone after a cycle.
- The fix
- If the dispenser door won't open or latch, the dispenser assembly or its spring may need replacing.
5.Water inlet valve not letting in enough water
The inlet valve opens to fill the tub. Its small screen can clog with sediment and the valve can weaken with age. A low fill means the wash pump sucks air and sprays weakly.
- Check it yourself
- Open the dishwasher a few minutes into a cycle (it will pause). On most models, water should cover the sump area at the bottom of the tub. If you barely see any water, a fill problem is likely. Make sure the supply valve under the sink is fully open.
- The fix · typical $150 – $250
- A clogged or weak inlet valve is replaced. It's a quick repair and a common part.
6.Weak or failing wash pump
The wash or circulation pump drives water through the spray arms. If its motor or impeller wears out, you'll get low pressure even with clean arms and a full tub. Sometimes the motor hums but won't turn.
- Check it yourself
- Listen during the wash. A healthy pump makes a steady swishing sound. A loud hum, grinding or a very quiet wash with clean filters and arms points to the pump.
- The fix · typical $260 – $450
- We test the motor and check for debris jamming the impeller first. If the motor has failed, the wash pump is replaced.
7.Heating element not heating the water
Many dishwashers use a heating element to raise water temperature during the wash. If it fails, every cycle runs cooler than designed. You may also notice poor drying, since the heater often helps there too.
- Check it yourself
- After a full cycle, carefully touch the dishes. They should be hot. With the dishwasher unplugged, look at the element in the tub floor (if your model has one exposed) for breaks or blisters.
- The fix · typical $170 – $290
- We test the element, its thermostat and the control before replacing anything. A failed element is a straightforward repair.
When to call a technician
Call us if the filter and spray arms are clean, the water is hot, and dishes still come out dirty, or if you hear grinding or humming during the wash. We'll check fill level, pump pressure and heater function, and give you a flat written price before work starts. The $79 diagnostic is credited to the repair.
45-day parts & labor warranty
Every repair carries a 45-day warranty on the parts we install and on our labor.
What the warranty covers →Common questions
Should I pre-rinse my dishes?
+
Scrape food off, but you don't need to rinse plates spotless. Most modern detergents work best with some food soil to act on, and many dishwashers adjust the cycle based on how dirty the water is.
Are pods better than powder or gel?
+
Pods are convenient and pre-measured, and they don't clump the way an opened box of powder can in humid weather. Any fresh, quality detergent works if the dishwasher is healthy. Gel is generally the weakest performer.
Why is there grit on my dishes?
+
Usually a dirty filter, or a drain hose with no high loop letting sink water flow back in. Clean the filter first, then check the hose under the sink.
How do I clean my dishwasher?
+
Clean the filter, wipe the door gasket and the bottom edge of the door, and run a hot cycle with a dishwasher cleaner once a month. That removes grease and mineral scale from areas you can't reach.
Is it worth repairing a dishwasher that doesn't clean?
+
Often the fix is free — a filter or spray arm. An inlet valve or heating element is a reasonable repair on most dishwashers. A wash pump on an entry-level unit over 10 years old is where we'll suggest comparing against a new one.
Related guides
Last reviewed 2026-10-07 by Mako Appliance Repair, Clearwater FL.
Rather not DIY it? We can usually come today.
$79 diagnostic credited to your repair · 45-day parts & labor warranty · Open 7 days · 7:30am–8:30pm