When dishes come out dirty, the dishwasher usually isn't getting enough clean water to the dishes. Clogged filters, blocked spray arms, cold water and loading habits cause most cases. A weak wash pump is the main repair possibility, and it's less common than people think.
| At a glance | |
|---|---|
| Can you DIY it? | Yes, for most causes |
| How urgent? | Low |
What are the most common causes?
A clogged filter. Most modern dishwashers have a manual-clean filter at the bottom. Many owners don't know it's there. Once it clogs, the machine recirculates dirty water.
Blocked spray arms. Food bits, seeds and broken glass plug the holes. Even a few blocked jets leave dirty spots.
Lukewarm water at the start. In old Boston buildings, hot water can take a long time to reach the kitchen, so the first fill is cold.
Loading that blocks the arms. A tall pan or cutting board can stop the lower arm from turning.
Old or too little detergent. Detergent loses strength when stored in humid spaces.
A failing wash pump or motor. You'll hear a weaker or uneven wash sound.
What fixes should I try first?
- •Remove, rinse and scrub the filter (usually a twist-out cylinder at the bottom).
- •Pull the spray arms and clear each hole with a toothpick.
- •Spin the arms by hand after loading to make sure nothing blocks them.
- •Run the kitchen tap until it's hot before starting the dishwasher.
- •Try fresh detergent, and use the right amount for soft water (less than you'd think).
- •Run an empty hot cycle with a dishwasher cleaner.
When should I call a technician?
Call if the filter and arms are clean but the wash sounds weak, if the water never feels hot at the end of a cycle, or if the dishwasher hums without washing.
Elliott's take
If you've never cleaned the filter, that's almost certainly your problem. I've pulled filters that looked like a compost bin. Make it a monthly habit and most of these calls disappear.
Related: Dishwasher repair · Dishwasher Leaking? How to Track It Down
Still getting dirty dishes? Call TrueFix Boston at (857) 810-1119 or book online.