If your dishwasher has started smelling a little off, leaving behind bits of food, or just doesn’t seem to clean as well as it used to, there’s a good chance something inside it is being overlooked.

And for a lot of people, it’s not obvious at first. Most of us tend to assume that dishwashers more or less take care of themselves. You load them, add detergent, run a cycle, and expect everything inside to come out clean. So when that starts to change, it’s easy to blame the detergent, the water, or even the dishes themselves.

But small signs usually show up before people realize something’s wrong. Maybe your glasses start coming out cloudy. Maybe your plates still have tiny bits of residue on them. Maybe there’s a damp, musty smell every time you open the door — even when the dishwasher looks clean from the outside. That’s usually a sign that buildup is collecting somewhere it shouldn’t be.

The good news is that this is often a very fixable problem. And once you know where to look, it’s one of those dishwasher issues that suddenly makes a lot more sense.