How to Fix a Dishwasher Not Cleaning Properly
When your dishwasher stops cleaning dishes properly, it's frustrating — but in most cases, the cause is simple and can be fixed without a technician. This guide walks through the 7 most common causes of a dishwasher not cleaning properly and how to fix each one.
1. Dirty or Clogged Filter
The number one cause of poor dishwasher cleaning in Australian homes is a clogged filter. The filter at the base of the dishwasher traps food particles during the wash. When it's blocked, water can't circulate properly, leading to dishes that come out with food residue, greasy smears or white film.
Fix: Remove the filter (usually a quarter-turn anticlockwise), soak in warm soapy water, scrub with a soft brush and refit. Do this every 1–3 months.
2. Blocked Spray Arms
The spinning spray arms distribute water throughout the dishwasher. The small holes in the arms can become blocked by mineral deposits, food debris or labels from glassware. Blocked spray arms mean parts of the dishwasher don't receive enough water.
Fix: Remove the spray arms (usually unscrew or unclip from below). Use a toothpick to clear each hole. Rinse under running water. Refit and confirm they spin freely.
3. Incorrect Dish Loading
Overloading, or loading dishes so they block the spray arms, is a surprisingly common cause of poor wash results. Cups and bowls facing upward collect water instead of draining. Pans blocking the spray arm prevent it from rotating.
Fix: Load dishes facing inward and downward. Never block the spray arms. Leave space between items. Run the spray arm by hand before closing the door to confirm it can rotate freely.
4. Wrong Detergent or Incorrect Amount
Using too little detergent, old or clumped powder, or a detergent not suited to your water hardness can all affect wash performance. Very hard water (common in some parts of western Sydney) may require extra rinse aid or a water softener tablet.
Fix: Use fresh dishwasher detergent — tablets or quality powder. Use rinse aid and keep the rinse aid reservoir topped up. In hard water areas, consider adding a dishwasher salt if your machine has a salt reservoir.
5. Water Not Hot Enough
Dishwashers need water at 55–65°C to properly dissolve grease and activate dishwasher detergent. If your hot water system is set too low or the dishwasher's heating element has failed, wash temperatures will be too cool for effective cleaning.
Fix: Run the hot tap at your kitchen sink before starting the dishwasher — this purges the cold water from the pipes and the machine fills with hot water immediately. If the problem persists, the heating element may need testing by a technician.
6. Low Water Pressure
Insufficient water pressure prevents the dishwasher from filling fully and the spray arms from operating at full force. This is more common in older homes or properties with shared water supply.
Fix: Check the inlet hose is not kinked. Ensure the water tap at the back of the dishwasher is fully open. If water pressure is a building-wide issue, contact your plumber or water provider.
7. Machine Needs Descaling
Mineral build-up (limescale) inside the dishwasher can affect spray arm performance, clog the filter housing and coat the heating element. This is more common in areas with hard water.
Fix: Run an empty dishwasher on a hot cycle with a commercial dishwasher cleaner (available at supermarkets) or place a cup of white vinegar on the top rack and run a hot cycle. Repeat every 1–2 months.
When Is It Time for a New Dishwasher?
If your dishwasher is over 10 years old and repeatedly failing to clean despite maintenance, it may be more cost-effective to replace it. Oceania Appliances stocks dishwashers from Hisense, Fisher & Paykel, Samsung and Bosch, with delivery across all of greater Sydney.
- Showroom: 2/14 Centre Place, Wetherill Park NSW 2164
- Phone / WhatsApp: 0422 489 492
- Email: support@oceaniaappliances.com.au