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Dishwasher Not Cleaning Dishes Properly? Here’s Why (And the Fix)

Symptoms:

Dishwasher Not Cleaning Dishes Properly? Here’s Why (And the Fix)

Cloudy glasses or gritty plates almost always mean a blocked spray arm, hard water, or a loading habit that’s shielding dishes from the water path, not a broken motor.

Dirty dishes and cups viewed from above, illustrating a dishwasher not cleaning properly
Risk
Low
Difficulty
Beginner
Estimated time
15 to 40 minutes

Before you start

Unplug the appliance, shut off the water supply if relevant, and stop immediately if you smell burning. If in doubt, call a qualified professional.

On this page

Cloudy glasses, gritty plates, or food residue baked onto dishes almost always point to a spray arm that isn’t spinning freely, hard water buildup, or a loading habit that’s blocking the water path, not a failed motor. Work through the checks below before assuming you need a part.

This page is part of our full dishwasher troubleshooting guide. If dishes are also coming out with a bad smell, our dishwasher smells guide covers that separately.

Quick Diagnosis Table

CauseLikelihoodDifficultyTypical Cost
Clogged or stuck spray armVery likelyEasy$0–20
Overloaded or blocked rackLikelyEasy$0
Hard water buildupLikelyEasy$5–15
Water not hot enoughPossibleEasy$0
Worn door gasketPossibleEasy–Moderate$15–35
Clogged inlet valve screenPossibleModerate$0–20
Wash motor losing powerRareProfessional recommended$100–250+

Repair or Replace?

Nearly everything on this page is free or under $35, so there’s essentially always a case for repairing over replacing. The one exception is a failing wash motor or pump assembly, which is a costlier, less common repair. On a dishwasher already past 8–10 years old, that’s the point to weigh a new unit instead.

Spray arm designs differ enough between Whirlpool, GE, Samsung, LG, Bosch, KitchenAid, Frigidaire, and Maytag that removal steps vary. Brand-specific guides are on the way.

Frequently Asked Questions

Why are my glasses coming out cloudy?

That's almost always hard water etching or mineral film rather than a cleaning failure. A rinse aid refill and an occasional citric acid cycle usually resolve it; permanent etching on glass, once it happens, can't be reversed.

Should I pre-rinse dishes before loading them?

No — modern detergents are formulated to work on food residue, and pre-rinsing can actually starve the wash cycle's soil sensor, causing it to under-clean. Scraping off large scraps is enough.

Why does only the top rack come out dirty?

That usually means the upper spray arm is clogged or not receiving enough water pressure, often because the lower spray arm or filter is restricting flow before water even reaches the top.

Can a full detergent dispenser cause poor cleaning if it won't open?

Yes — if the dispenser door is obstructed by a tall dish or utensil, some or all of the detergent never enters the wash, and you'll see food residue across most of the load.

How do I know if it's hard water versus a dirty filter?

Hard water leaves a white, chalky film on the tub interior and heating element; a dirty filter leaves food particles redeposited on dishes. Both often need addressing together.

The information provided here is a diagnostic aid and does not replace the intervention of a qualified professional.

Tools needed

Probable causes

First checks

Step-by-step diagnosis

  1. Remove each spray arm per your model's manual (usually a clip or twist-off cap) and clear jets with a toothpick or thin wire, then rinse under the tap.
  2. Soak the spray arms in a vinegar solution for 20–30 minutes first if the buildup looks like hard water scale rather than food debris.
  3. Run an empty cycle with a dishwasher-safe cleaner or citric acid product to descale the heating element, tub, and interior spray paths.
  4. Check water temperature at the kitchen tap nearest the dishwasher with a thermometer — it should read at least 120°F (49°C).
  5. If cleaning and temperature checks don't resolve it, inspect the water inlet valve's screen filter, where the fill hose connects, for sediment restricting flow.

Mistakes to avoid

When to stop

Parts potentially involved

When to call a professional

If the simple checks didn’t solve it, if the fix involves electrical wiring, gas, or the refrigerant circuit, or if you have any doubt at all: stop there and hand the appliance to a qualified repair professional.

Related guides

Error codes for this appliance

The information provided here is a diagnostic aid and does not replace the intervention of a qualified professional.

Sam Radford — DiagnosFix

Sam Radford — DiagnosFix

Technical reviewer

Last verified: 2026-07-17