What Should You Do If Your Dishwasher Leaves Dishes Dirty?

Dirty dishes coming out of a dishwasher almost always trace back to one of five causes: a clogged filter, cold or low water, poor loading, too little or too much detergent, or a blocked spray arm. Work through the checks below in order. Most people fix the problem within the first three steps.

Start with the basics

1. Clean the filter. Pull out the filter assembly at the bottom of the tub and rinse it under hot running water with a soft brush. Food and grease film here recirculates onto every dish. Check it weekly if you pre-rinse heavily.
2. Run the tap hot first. Turn on the kitchen hot tap until the water is genuinely hot, then start the dishwasher. Most machines draw only a few litres at the start, and cold water cannot dissolve detergent or melt grease.
3. Check the spray arms. Spin them by hand and look for blocked holes. Clear them with a toothpick or a thin wire, then run water through them.

Fix loading and detergent

4. Load for water flow. Face soiled surfaces toward the spray, angle bowls and cups downward, and keep large items from blocking the arms. Never let a tall pan block the detergent dispenser door.
5. Stop overloading. If dishes touch each other, water cannot reach the surfaces between them. Leave gaps and run a second, lighter load if needed.
6. Use fresh detergent. Powder and pods absorb moisture and lose strength over time. Store them dry, and use a rinse aid to help water sheet off and dry.
7. Match detergent to water hardness. Hard water needs more detergent and a rinse aid; very soft water needs less, or the detergent can etch glass and leave a film.

Clear buildup and check the machine

8. Deep clean the machine. Once a month, run an empty hot cycle with a dishwasher cleaner or a cup of white vinegar placed upright in the top rack. This dissolves grease and mineral scale.
9. Check the water inlet and drain. Confirm the water supply valve is fully open, and look for a kinked inlet hose or a blocked drain hose. Standing water at the end of a cycle points to a drain problem.
10. Confirm the cycle and temperature. Use a normal or heavy cycle with a heated dry or high-temp wash option. Eco and quick cycles use less water and heat, so they clean lightly soiled dishes only.

What NOT to do

• Do not use dish soap or hand-washing liquid: it foams over and can damage the pump.
• Do not pre-rinse every dish until it is spotless. Modern detergents need some soil to work, and enzymes need contact time.
• Do not pack the racks tight to save a cycle.
• Do not ignore a persistent smell or standing water; both signal a filter or drain issue.

When to call a professional

Call a qualified appliance technician if the machine does not fill, does not drain, leaks, trips the electrical breaker, or still leaves dishes dirty after you have cleaned the filter, checked the spray arms, and run a hot cycle with fresh detergent. Do not open panels or work on wiring or water connections yourself if you are unsure; unplug the machine and shut off the water supply first.

Try the filter and hot-water steps today, then run one test load with fresh detergent and rinse aid. If the result is still poor, book a service call.