10 dishwasher mistakes keeping your dishes dirty (and costing you money)

If your dishwasher isn’t delivering spotless plates and crystal-clear glasses, the machine might not be the problem. In our testing, we’ve found that performance issues often come down to user habits—how dishes are loaded, which cycle is selected, or whether the filter has been cleaned recently.

Here are 10 common dishwasher mistakes—and what to do instead.

1. You’re pre-washing everything

If you’re pre-rinsing plates until they look clean before loading them, you can stop. Modern dishwashers and detergents are designed to tackle food residue. In fact, many newer machines use soil sensors to detect how dirty your load is and adjust the cycle accordingly. If your dishes go in nearly spotless, the sensor may shorten the cycle, resulting in less effective cleaning.

There’s a difference between scraping and rinsing:

• Scrape large food scraps like rice, pasta, or bones into the trash or compost.
• Skip the full pre-rinse under hot water.

Over-rinsing wastes water and can reduce how effectively your dishwasher cleans.

2. You’re overloading the racks

A dishwasher packed to the brim might feel efficient, but overcrowding is one of the fastest ways to end up rewashing dishes.

Water needs space to circulate. If dinner plates are pressed tightly together or bowls are nested inside one another, spray arms can’t reach every surface. In testing, we consistently see better results when dishes are spaced with small gaps between them.

If you’re trying to squeeze in one more pan, it’s probably too much.

3. You’re loading dishes facing the wrong direction

The orientation of plates, bowls, and glasses matters more than most people think.

• Plates should face inward toward the center spray arm.
• Bowls and cups should be angled downward so water doesn’t pool.
• Mix utensils in the basket to prevent spoons from nesting together.

If you have a flatware tray, use it to separate utensils for better cleaning coverage.

4. You always use the same cycle

Defaulting to the Normal cycle for everything can leave heavily soiled dishes less than spotless.

Different dishwasher cycles exist for different soil levels:

• Heavy or Pots & Pans cycles run longer and use higher temperatures.
• Eco cycles use less water and energy but typically run longer.
• Sensor cycles automatically adjust based on how dirty the load is.

If your baked-on casserole dish comes out dirty, switching to Heavy may solve the problem.

5. You’re tossing detergent in the wrong place

Dishwasher pods should go in the detergent dispenser, not loose in the bottom of the tub. The dispenser releases detergent at the correct time during the main wash cycle.

If you throw a pod directly into the tub, it may dissolve too early. Use the dispenser for pods, powder, or gel. Fill only to the recommended line, and for the love of god don’t use regular dish soap—it will create excessive suds.

More detergent doesn’t mean cleaner dishes, especially in homes with soft water.

6. You’re skipping rinse aid

If your glasses come out spotted or your plastic containers are still wet at the end of the cycle, rinse aid may help.

Rinse aid allows water to sheet off dishes instead of forming droplets that leave mineral spots. It’s especially useful in homes with hard water.

Even if your detergent includes a rinse component, adding a separate rinse aid often improves drying performance. Most machines allow you to adjust the rinse aid setting.

7. You haven’t cleaned the filter

Many modern dishwashers have manual filters that trap food particles. If you’ve never removed yours, it’s time.

A clogged filter can lead to food redepositing on dishes, lingering odors, and poor cleaning performance.

Most filters twist out from the bottom of the tub and can be rinsed under warm water. Checking it monthly (or weekly!) is usually enough for most households.

8. You’re ignoring the spray arms

Spray arms can become blocked with food debris or mineral buildup. If dishes on the top rack aren’t getting clean, a partially clogged spray arm may be the issue.

Most spray arms can be removed and rinsed. Use a toothpick or small brush to clear blocked holes. It’s a simple maintenance step that can noticeably improve cleaning performance.

9. You’re putting plastics on the bottom rack

The bottom of the dishwasher is closest to the heating element, so you’ll want to place plastics on the top rack to prevent warping and reserve the bottom rack for heavier items like ceramic plates and stainless-steel pots.

If you’ve ever pulled out a melted food storage lid, bottom-rack placement was likely the reason.

10. You’re running small loads or waiting too long between loads

Running half-empty loads wastes water and energy. But waiting until the dishwasher is completely crammed can lead to poor cleaning.

Aim for a mostly full load with proper spacing between items. Modern Energy Star dishwashers are generally more water-efficient than handwashing, so running regular full loads is typically the most efficient choice.

If your machine has a delay start feature, consider using it to run cycles during off-peak electricity hours.

The bottom line

A dishwasher is only as effective as the way it’s used, so before blaming your machine for cloudy glasses or crusty plates, take a closer look at your habits. A few small adjustments can make a noticeable difference—no new appliance required.