Why Won’t My Dishwasher Drain?
TechXpert verified by Rob Ilie
A dirty or clogged filter, a blocked drain line, a clogged garbage disposal, or a faulty dishwasher drain pump can cause water to collect in your dishwasher. If your dishwasher is draining slowly or won’t drain at all, there are a number of faults that could be to blame — here’s where to start your investigation.
The Dishwasher Drain Block Dilemma
First things first: let’s diagnose the issue at hand, beginning with some of the most common problems.
Dirty or Clogged Filter
Just like any other system in your home, your dishwasher can get grimy with buildup. Small food particles, labels on jars, very dirty dishes, and other kinds of scum accumulate and can clog the filter in your dishwasher. When this happens, you can bet it won’t drain as well as it should.
Blocked Drain Line
Food particles, scum, and other materials can eventually block your drain line, causing the water to pool in the unit. And since it’s in the line, you won’t be able to see what’s causing the trouble.
Food Particles in the Garbage Disposal
It’s possible that some food remnants have lodged in the line between the garbage disposal and the dishwasher, especially if you don’t run the garbage disposal long enough to grind up all of the material.
Faulty Dishwasher Drain Pump
Less often, it’s a faulty dishwasher drain pump that’s to blame for your drainage problem. This part uses an impeller to drain water from your system, and when that fails due to damage or buildup, your dishwasher won’t drain properly.
Getting Your Dishwasher Back on the Job
Now that you have a better idea of the culprit, let’s get your dishwasher draining as it should! Here’s what you can do, depending on the cause of the problem.
What to Do if Your Have a Dirty or Clogged Filter
If your dishwasher filter is dirty or clogged, all you need to do is clean it:
Locate your dishwasher filter (the cylindrical fixture) in the basin of your dishwasher, and remove it by twisting it to unlock and then pulling it out.
Hand wash the filter with hot, soapy water and rinse clean.
Once it’s all clean and clear, you can plug the filter back into your dishwasher and you’re back on track.
What to Do if the Drain Line is Blocked
A blocked line means it’s time for a deep clean. If you’re up for the task, remove the drain hose from under the sink and run water or a drain snake through it until the clog is cleared. You could also try attaching a shop vac to you drain hose in an effort to suck out the blockage.
If the issue is more serious than a bit of debris in the way, contact your local plumber. Mineral and sediment buildup may have caused damage to your drain pipe, and in that case, you’ll need to have it replaced.
What to Do if Your Garbage Disposal is Blocked
This is often an easy fix — just run it! After running the garbage disposal, let water flow down the drain for about 15 to 20 seconds to flush everything out.
Another helpful tip: squirt a generous amount of dish soap right into the garbage disposal while it’s running. If you keep the water running, the suds will help break up the grease and loosen the clog. Dumping a tray of ice down there can also help keep the bladed clean!
If it appears that your garbage disposal is clogged deep inside, you may have to clear the clog manually.
What to Do if You’ve Got a Faulty Dishwasher Drain Pump
If a faulty or defective dishwasher drain pump is to blame, then you’re probably best off replacing the part.
Dishwasher drain pump replacements are jobs for professional plumbers. Faulty dishwasher drain pumps aren’t very common, but they’re also not simple fixes -- leave this one to the pros.
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