Dishwasher Not Cleaning Properly? Here's How to Fix It

If your dishwasher is leaving dishes dirty, spotty or with a film of residue, there are several likely causes — and most can be fixed without calling a technician. Here's how to diagnose and solve the most common dishwasher cleaning problems.

1. The Filter Needs Cleaning

This is the most common cause of poor dishwasher performance. The filter sits at the bottom of the dishwasher and traps food particles. If it gets clogged, water can't circulate properly and dishes come out dirty.

Fix: Remove the filter (usually a twist-off cylinder at the bottom of the tub), rinse it under warm water, and scrub gently with an old toothbrush. Clean it at least once a month.

2. Spray Arms Are Blocked

Dishwashers clean dishes by spraying water through rotating arms with small holes. If these holes get clogged with mineral deposits or food debris, the spray pattern is disrupted.

Fix: Remove the spray arms (they usually pull or unscrew off) and rinse them under water. Use a toothpick or thin wire to clear any blocked holes. Reattach firmly.

3. Incorrect Loading

How you load the dishwasher matters a lot. Dishes blocking the spray arms, bowls facing the wrong direction, or items nested together all prevent proper cleaning.

Fix: Load larger items on the bottom rack facing the centre. Place cups and bowls upside down and angled. Make sure no tall items block the spray arms from rotating.

4. Wrong Detergent or Not Enough

Using the wrong type of detergent, or too little, results in poor cleaning. Cheap detergents can also underperform in hard water areas.

Fix: Use quality dishwasher tablets or powder. For hard water areas, use a detergent with built-in rinse aid and salt, or add rinse aid and dishwasher salt separately.

5. Rinse Aid Is Empty

Rinse aid helps water run off dishes smoothly, preventing spots and film. If your rinse aid dispenser is empty, dishes will often come out wet, spotty and dull.

Fix: Refill the rinse aid dispenser (usually a small compartment on the inside of the door). Top it up every few weeks.

6. Water Temperature Is Too Low

Dishwashers need hot water to dissolve grease and activate the detergent. If your water heater is set too low, cleaning performance suffers.

Fix: Check that your hot water system is set to at least 60°C. Run the kitchen tap until hot water arrives before starting a cycle, so the first fill is hot.

7. The Dishwasher Needs a Maintenance Wash

Over time, grease and mineral scale can build up inside the dishwasher itself.

Fix: Run an empty cycle with a dishwasher cleaner (like Finish Dishwasher Cleaner) or a cup of white vinegar placed upright on the top rack. Do this monthly.

When to Replace Your Dishwasher

If your dishwasher is more than 10–12 years old and cleaning performance is poor despite maintenance, it may be time for a replacement. Modern dishwashers are significantly more water-efficient and effective than older models.

Shop Dishwashers at Oceania Appliances

We stock a wide range of dishwashers to suit all budgets and kitchen sizes. Free Sydney delivery, 3–6 month warranty on every purchase. Shop online or visit our Wetherill Park showroom.