You open the door expecting clean dishes and get a pool of grey water in the bottom, with bits of last night’s dinner floating in it. It smells within a day. Here’s the good news: of the four things that usually cause this, three cost nothing to fix and one of them isn’t even the dishwasher’s fault.
First, get the water out
Switch the dishwasher off at the breaker, or unplug it if you can reach the cord. Lay towels along the floor in front of it, because whatever you don’t scoop will end up there. Use a cup or a small jug to bail the water into a bucket, and when it’s too shallow to scoop, press towels into the bottom until the tub is dry. You need to see the floor of the machine before you can do anything else, and you don’t want to be feeling around in dirty water near a heating element.
How a dishwasher actually drains (in one paragraph)
At the end of a cycle a pump pushes water out of the tub, through a filter that catches food, along a hose that loops up high under your counter, and into either your garbage disposal or a dedicated fitting on the drain pipe. Many kitchens also have an air gap, the small chrome cylinder sitting on the sink, which stops dirty sink water siphoning back into the dishwasher. Every one of those is a place water can get stuck, and only the last of them is inside the machine.
Four places it’s usually stuck
1. Run the garbage disposal first
This takes ten seconds and solves it more often than anything else on this list. If your dishwasher drains into the disposal, and the disposal is packed with scraps, the dishwasher has nowhere to send water. Run cold water and the disposal for about thirty seconds, then start a drain or rinse cycle and watch. If the water goes, you’re done.
The exception worth knowing. If the dishwasher is newly installed and has never drained properly, not once, the problem is almost certainly the knockout plug. Disposals arrive with the dishwasher inlet sealed by a plug that the installer is supposed to punch out. When it’s missed, the machine spends every cycle pumping against a solid wall. Nothing is broken, and no part is needed.
2. Clean the filter in the floor of the tub
Take the bottom rack out and look at the floor of the machine. Most dishwashers made in the last fifteen years have a cylindrical filter you twist a quarter turn and lift out, usually with a flat mesh screen underneath it. Expect to find a grey paste of grease and food, and sometimes a popcorn kernel, a seed, or a shard of glass, so look before you put your fingers in. Rinse both parts under hot water, scrub the mesh with an old toothbrush, and seat the filter back with a firm twist until it locks. Manufacturers expect this every month or two. Most people have never done it once.
3. Check the air gap on the sink
If you have that small chrome cylinder next to the tap, twist the cover off and lift out the cap underneath. There’s a short channel in there that clogs with the same grease and food. Clear it with a bottle brush and rinse. A blocked air gap is easy to miss because the dishwasher sounds completely normal while it fails to drain, and some people run their whole kitchen for years without knowing the thing has a lid.
4. Look at the drain hose under the sink
Open the cupboard and follow the ribbed hose from the dishwasher. You are checking two things. First, a kink or a crush point, usually where somebody pushed a bottle of cleaner against it. Second, whether the hose rises in a high loop before it comes back down to the disposal or drain. That loop is what stops sink water flowing backwards into your machine. If the hose runs flat along the floor of the cupboard, that alone can stop proper draining.
What it usually turns out to be
In our experience it’s the filter or the disposal far more often than anything else, and those two need no parts at all. After that comes the air gap, then the hose, and only then the drain pump. A pump that has genuinely failed usually makes itself heard, with a hum or a grinding at the point in the cycle where the water should leave. Complete silence at that moment more often means the machine isn’t being told to drain, which points at the control board instead.
Should you keep using it?
No. Running another cycle just adds clean water to a tub that’s already full, and on some machines that pushes water past the door seal onto your floor. Leave it off with the door open so it dries out, which also stops the smell setting in. (If the dishwasher isn’t the only thing misbehaving, our list of common appliance problems covers what each symptom usually means.)
Repair or replace?
Repair, almost always. Three of the four causes above cost nothing but twenty minutes, and a drain pump is one of the less expensive parts in the machine. Replacing only makes sense on a dishwasher well past ten years old that has already started leaking or stopped getting dishes clean. If that sounds like yours, ask us and we’ll give you a straight answer.
What a repair like this costs
With FixAIro there’s a service call fee for a technician to come out and confirm the problem, and it’s waived if you go ahead with the repair. Before the visit we give you a labor range for the repair. Parts are priced separately, and you approve the final price before any work starts. Nothing gets added at the door.
How to get it fixed
Call us and have three things ready: the brand and model number (on a sticker along the edge of the door), whether it drains into a garbage disposal, and what you found in the checks above — what came out of the filter, whether running the disposal changed anything, whether you hear the pump try. From those we can tell you the most likely cause and what it will cost before anyone drives out. Here’s how the whole repair works, from the first call to the finished job.