Dishwasher Not Cleaning Properly? Try These Expert Fixes Before Replacing It

When your dishwasher stops doing its one job — cleaning — frustration builds fast. Cloudy glasses, greasy plates, and leftover food make it seem like your appliance is finished. But in most cases, the problem isn’t serious and can be fixed in under an hour.
Here are the most common causes and practical steps to get your dishwasher cleaning like new again.

Check and Clean the Spray Arms
The spray arms distribute water pressure throughout the dishwasher. When small food particles, seeds, or mineral deposits clog the nozzles, the water can’t reach your dishes effectively.
Remove the arms and rinse them under warm water. Use a toothpick or a fine wire to clear the small holes. Once they’re unclogged, you’ll likely see an immediate improvement in cleaning performance.

Inspect the Filter and Drain
Most dishwashers have a removable filter at the bottom that catches debris. Over time, this filter can clog and reduce water circulation.
Take it out, wash it under hot water, and scrub gently with a soft brush. Don’t forget to check the drain area below it — buildup here can prevent proper drainage and leave dirty water inside the tub.

Test the Water Temperature
Dishwashers clean best when the water temperature is around 120°F (49°C). If your home’s hot water supply is cooler than that, grease and detergent won’t dissolve properly.
Run the hot water at your sink before starting a load to make sure the dishwasher starts with hot water already flowing.

Use the Right Detergent (and the Right Amount)
Not all detergents perform equally, and using too much can create residue. Powder detergents or high-quality pods often give better results than liquid types.
Also, avoid combining rinse aid and multi-action tablets — it can oversaturate the water with chemicals and actually reduce cleaning efficiency.

Check the Inlet Valve and Float Switch
If your dishwasher isn’t getting enough water, it can’t wash properly. The inlet valve controls the water flow, while the float switch prevents overfilling.
If either part is faulty, you may hear the machine running but notice very little water inside. Replacing these parts is often straightforward for a technician.

Run a Cleaning Cycle with Vinegar and Baking Soda
Over time, detergent residue and mineral buildup reduce efficiency. Run an empty cycle with one cup of white vinegar, followed by a short cycle with a few tablespoons of baking soda.
This deep-cleans the interior, deodorizes the machine, and helps restore proper spray pressure.

Don’t Overload the Racks
Even the best dishwasher can’t clean properly if dishes are stacked too tightly. Water needs space to circulate.
If you frequently find soap spots or unwashed corners, try spacing dishes more evenly and alternate the direction of bowls and cups for better coverage.

Frequently Asked Questions

Q: My dishwasher runs but dishes stay dirty. What’s the most likely cause?
A: Usually clogged spray arms or a dirty filter. These restrict water flow and prevent detergent from circulating properly.

Q: How often should I clean the dishwasher filter?
A: Every two to four weeks. It’s a small task that prevents odor and keeps water flowing freely through the system.

Q: Why are my glasses cloudy after a wash?
A: It’s often caused by hard water or too much detergent. Try using a rinse aid and ensure your water temperature reaches at least 120°F.

Aidan Appliance Repair and Installation provides professional dishwasher repair, maintenance, and installation across Guelph and surrounding areas.
131 Raymond St, Guelph, ON | 1 (289) 208-3700