One of our tips for "How to Know When to Replace Your Dishwasher" was to check that your dishwasher is draining properly by looking out for water leftover after it runs a cycle. But the truth is, not all standing water is a bad sign. After a few awesome commenters asked about their own water woes, we're here to help set the record straight.
How much water should there be?
Anywhere around 1 cup of water leftover after a cycle is normal. It's there to keep the seals from drying up and your dishwasher will pump it out immediately before you get started on a new load. But if you've got a lot more than 1 cup, there could be an underlying problem like a broken motor.
We don't use our dishwasher often. The water gets funky.
Check the manual to see if there's a way to drain the dishwasher manually and get rid of the water completely (Look for a "Cancel/Drain" button). If you do that, you might want to pour a few cups of fresh water in there to keep the pump just barely submerged. Do this "drain and pour" as often as you see fit.
What if the amount of water is slowly growing?
It depends if the water coming in to the dishwasher is clean or dirty.
If it's clean, that usually means the fill valve isn't shutting off completely and leaking new water into the dishwasher. To keep your water bills down, install a new fill valve.
If the water is dirty, it's is a sign that water is leaking into your dishwasher, most likely from the garbage disposal or the sink. This is a plumbing and drainage issue that you'll want to get checked out by a pro.
We just installed our garbage disposal. Could that be the problem?
Maybe. New disposals come with a plug in the connection for the dishwasher drain hose. If there was an oversight and the plug was never removed, your dishwasher can't drain.