Let's start with a quick review of how a dishwasher works:
- Detergent and water are mixed together within the dishwasher
- The dishes are blasted with this cleaning solution for roughly two hours
- The dirty waste water is drained out
Here are some steps to take to address the issue:
ALWAYS Scrape your dishes before loading.
Yes, those corn kernels and other food bits aren't going to be digested by your dishwasher. They're just going to clog up the dishwasher, preventing the water from blasting your dishes. No blasting means no clean dishes.
Yes, it says this in the manual, but you ignored it. Take a dirty sponge or rag and wipe off your dirty dishes before loading them into the dishwasher. Yes, your hands might get a little dirty! Suck it up.
Use GOOD dishwasher detergent
Lousy detergent does a lousy job cleaning dishes, and no, it is not all the same. Try different brands until you find one that works well. I've been happy with the Target "pack" style detergent. Recently, I've been less happy with Cascade.
Properly load your dishwasher
Your dishes should feel like they're riding in a bus, not like they're jammed into an overloaded elevator.
Make sure there is at least a half inch between the surfaces of your dishes. Nesting will prevent the dishwasher from blasting all surfaces. Also, don't allow your spoons, forks and knives to "nest together". You can fill your dishwasher, no worries, but don't jam everything in.
Clean the filter
Some dishwashers have a filter or screen in the bottom sump that should be cleaned periodically. Read your dishwasher's manual and see your dishwasher has one. It's likely full of awful food waste from years gone by. Also, check the water nozzles in your dishwasher and make sure they aren't clogged with gunk. If they are clogged, you'll need to do something to unclog them.
Use JetDry or similar
Yes, it exists for a reason - it basically helps the water and detergent scrub your dishes harder. Some detergent has this built-in, but most does not. Using it is simple and inexpensive.
Energy saving tips:
- Fully load your dishwasher before running it.
- Don't use "super scrub" or other modes that just mask your dishwasher's issues.
- Don't use heated-dry mode. It's an energy suck. Air drying can be much more efficient.
- Use the timer to run the dishwasher over-night. I have mine run at about 6 AM, and then I can immediately empty it in the morning as I brew my coffee.
Leaks, a lack of water, or a lack of water pumping are much more serious issues. Professional repair or replacement is likely the right course of action in these cases.