Why Isn’t My Dishwasher Cleaning Properly

What Does “Not Cleaning Properly” Usually Mean?

Before troubleshooting, it helps to define the problem clearly. Poor cleaning typically shows up as one or more of the following:

• Food residue left on plates or cookware

• Cloudy glassware or streaks

• Detergent not fully dissolving

• Greasy film on dishes after a cycle

Each symptom points to a specific issue. Addressing the right cause early can prevent unnecessary repairs.

Check Loading and Spray Arm Movement First

Incorrect loading is one of the most common reasons dishwashers fail to clean well.

Dishwashers rely on rotating spray arms to distribute water evenly. If dishes block those arms, water cannot reach all surfaces.

Common mistakes include:

• Large items blocking spray arm rotation

• Bowls stacked too closely together

• Utensils nested inside each other

• Make sure spray arms can rotate freely

• Place large cookware at the sides or back

• Angle dishes so water can reach all surfaces

Even a well-maintained dishwasher cannot clean effectively if water flow is restricted.

Inspect and Clean the Filter and Spray Arms

If loading is correct and dishes are still dirty, internal blockages are often the cause.

Food particles and grease collect in the filter over time. Spray arm holes can also become clogged with debris or mineral deposits. When this happens, water pressure drops and cleaning performance suffers.

• Remove and rinse the filter under warm water

• Use a soft brush to clear debris if needed

• Check spray arm holes for blockages and rinse them clean

Regular cleaning prevents buildup that slowly reduces performance.

Confirm Water Temperature and Water Supply

Dishwashers need hot water to dissolve detergent and break down grease.

If incoming water is too cool, detergent may not activate fully. Grease can remain on dishes even after a full cycle.

• Run hot water at the sink before starting a cycle

• Make sure the water supply valve is fully open

• Check hoses for kinks or restrictions

Inconsistent water pressure or temperature can lead to uneven cleaning results.

Review Detergent and Rinse Aid Use

Using the wrong detergent, or using it incorrectly, often leads to residue and poor results.

• Using too much detergent

• Using expired detergent

• Using detergent not designed for automatic dishwashers

Hard water can also reduce detergent effectiveness.

• Use detergent recommended for your dishwasher

• Follow dosage instructions carefully

• Add rinse aid to improve drying and reduce spots

Rinse aid helps water sheet off dishes instead of forming droplets that leave residue behind.

Clean the Dishwasher Interior Regularly

Even if dishes are loaded correctly, residue inside the dishwasher can affect performance.

Grease, soap scum, and mineral deposits can build up on interior surfaces. Over time, this interferes with water flow and cleaning action.

• Run a monthly cleaning cycle

• Use dishwasher-safe cleaners or white vinegar

• Avoid harsh chemicals like bleach in stainless steel interiors

Regular cleaning keeps internal components working as intended.

Avoid Long Periods of Inactivity

Dishwashers that sit unused for long periods often perform worse when restarted.

When water sits inside the machine:

• Mineral deposits can harden

• Seals may dry out

• Spray arms may not rotate smoothly

• Run the dishwasher regularly, even if lightly loaded

• This keeps components moving and prevents buildup

When Smart Features Can Help Diagnose Issues

Once basic mechanical and usage issues are addressed, smart tools can support ongoing maintenance.

Modern LG dishwashers include features such as Smart Diagnosis and app-based monitoring through LG ThinQ. These tools help identify patterns that may not be obvious during daily use.

Smart features can help by:

• Flagging performance changes early

• Providing diagnostic data for support teams

• Sending maintenance reminders

These tools do not replace basic care, but they can reduce guesswork when problems appear gradually.

Know When Professional Help Is Needed

Some issues require trained service support.

• Persistent leaks

• Electrical issues or exposed wiring

• Error codes that do not clear

• Repeated cleaning failures after basic fixes

Using authorized technicians protects your appliance and helps maintain warranty coverage.

Keeping Your Dishwasher Cleaning Properly Over Time

Consistent care prevents most cleaning problems before they start.

Good habits include:

• Loading dishes correctly

• Cleaning filters and spray arms regularly

• Using the right detergent and rinse aid

• Running the dishwasher consistently

• Responding quickly to changes in performance

A dishwasher that receives regular attention will clean more effectively and last longer.