Why Is My Dishwasher Not Draining? What Should I Check First?

You open the dishwasher door, pull out the bottom rack, and there it is: a pool of murky water sitting where it shouldn’t be. A dishwasher that won't drain is a common kitchen problem, and water in the bottom of the dishwasher doesn’t always mean the machine is broken. When your dishwasher won’t drain, the cause is usually simpler than it looks.

This guide walks you through what’s normal, what causes the problem, what to check first, and when it’s time to call a pro. Most drain problems start with a part you can reach without any tools, so the fix may be closer than you think.

Before you take anything apart, it helps to know how much water is actually normal.

Is It Normal to Have Water in the Bottom of Your Dishwasher?

A small amount often is. Most dishwashers are built to hold a little water in the sump, the low basin under the filter, so the seals don’t dry out between cycles.

When that little bit turns into a puddle, things go wrong. That being said, why is there standing water in the bottom of the dishwasher?  Most of the time, the depth tells. A thin layer of water under the filter is normal. If water covers the filter or the tub floor, it's not draining properly.

Spotting water in the bottom of the dishwasher after a cycle is your cue to take a closer look. Here’s a quick way to read what you see.

If what you see matches the last three rows, something is blocking the drain path. The good news is that most of these causes are easy to find.

Water in the Bottom of the Dishwasher When It’s Not in Use?

There will usually be some water on the bottom of the dishwasher when it is not being used. The water source is usually outside the machine. The water comes from your sink or garbage disposal because the dishwasher hasn't been used.

This is called reverse flow. When the tub is not in use, water from the sink drain backs up into the tub through the drain hose. Often, it's how the hose is set up under the sink. We'll talk about how to fix this below.

Now you know what should and shouldn’t be happening. Let’s look at what actually prevents a dishwasher from draining.

Why Won't My Dishwasher Drain?

Most drain problems fall into two groups. Blockages are the most common, and you can usually clear them yourself. Part failures are rarer, and they usually need a pro.

If you’ve been asking why your dishwasher isn't draining water, assume it’s a blockage. Food scraps, grease and small debris build up over time and slow the flow until the water stops moving. In most kitchens, that’s the simple answer to why a dishwasher won’t drain.

Can a Blocked Drain Hose Stop the Water From Draining?

Yes, and it’s easy to miss because the hose sits out of sight. It runs from the back of the dishwasher to the sink drain, and any problem along that path can keep your dishwasher from draining properly.

These are the spots where hose trouble usually starts:

1. Behind the unit: kinks form when the dishwasher is pushed back into place.
2. Through the cabinet wall: the hose can get crushed or pinched where it passes through.
3. At the sink end: grease and food buildup narrow the opening until little water gets through.

A quick look at each spot can save you from taking the whole machine apart.

Pump Running but Dishwasher Not Draining?

When your dishwasher isn't draining, but the pump is running, the sound it makes is a useful clue. Listen closely during the drain phase.

A steady hum usually means the motor is working, but something is jamming the impeller, the small spinning part that pushes water out. Bits of glass, bone and seeds are common culprits. Silence points to a motor or power fault instead, which is a job for a professional. We cover that in the section on when to call a pro.

You can rule out most of these causes in a few minutes, as long as you check things in the right order.

What Should You Check First When Your Dishwasher Won’t Drain?

Start inside the tub and work your way out. Start with the parts you can reach by hand, then move to the ones under the sink. Most of the time, you won’t need to go past the first two. Before you start, switch off the dishwasher at the breaker. You’ll be working near the tank.

Here’s what to do if your dishwasher won’t drain, in order.

Run a short rinse after each fix to see if the water clears; that will tell you what to do next time your dishwasher won’t drain: stop there, or move down the list.

Signs Your Dishwasher Drain Filter Is Clogged

If someone says, “My dishwasher won’t drain,” check this first. It sits at the bottom of the tub, catches food before it reaches the pump, and people often forget it. Most of the time, you'll see:

1. There is water in the tub after the cycle is over.
2. Plates and glasses have little bits of food stuck to them.
3. A bad smell when you open the door.

It smells like old food is going bad inside. A dirty filter is almost always the cause of a dishwasher that won't run and smells bad. So you can run hot water over it and use an old toothbrush to clean the mesh. How often should you clean a dishwasher filter? Most homes can handle once a month. If you load plates without scraping them, check it every week or two.

Where Is the Air Gap, and How Do You Clear It?

Check the countertop next to your faucet. A small metal or plastic cap there is the air gap. Not every kitchen has one.

Pull the cover straight up, twist off the inner cap, and clear out the gunk. If water ever shoots out of it mid-cycle, the clog is further along, in the hose or the disposal. Still have water in the tub after all this? Then it’s likely a partial blockage further down the line, and that needs a slightly different fix.

How Do You Fix a Dishwasher That Won’t Drain Completely?

Most of the time, you can fix a dishwasher that won't drain fully on its own if only one part has stopped working.

Start with the sink drain hose. If it goes up in a curve, that's called a high loop. Then it should go down to the drain. This loop stops sink water from going back into the dirty tub. Most of the time, your dishwasher won't drain fully if the hose lies flat on the cabinet floor. Clamp or zip-tie the middle of the hose and lift it as high as you can.

If you are wondering how to fix a dishwasher that won’t drain, here are a few simple things you can do:

1. Raise the drain hose into a high loop.
2. Run the sink for a bit with hot water before starting a cycle.
3. Before loading the plates, remove any remaining food, then put them in the dishwasher.

Dishwasher Not Draining After Cleaning the Filter?

Clean the filter, clear the sump, and still have a puddle. Now the check valve is a likely suspect. It’s a small flap near the pump that lets water out and keeps it from flowing back in, and one stuck piece of food is enough to hold it closed. That’s how you end up with a dishwasher that won't drain but has no blockage you can actually see.

The drain solenoid, the part that opens the drain on some models, can also fail. So can the spot where the hose connects to the pump, which can clog up without you noticing. Both sit behind the dishwasher, and getting to them means pulling the whole unit out. Let a technician handle that part.

Is It Safe to Run a Dishwasher With Standing Water?

No. More water goes into a tub that can’t empty, and you could be mopping the kitchen floor afterwards. Your dishes get sprayed with the dirty water, too. Turn it off at the breaker, scoop the water out with a mug, and use an old towel for the bottom.

And check your kitchen sink. If that’s draining slowly too, the dishwasher isn’t the real problem. The garbage disposal might be.

Can a Garbage Disposal Cause Dishwasher Drainage Problems?

Yes, and it happens more often than most people expect. Most dishwashers are built with a garbage disposal under the sink and can drain on their own, so they share the same exit. When the disposal has a problem, your dishwasher feels it too, which is why garbage disposal and dishwasher not draining issues so often show up together.

Here’s how to match what you’re seeing with the likely cause.

The last row is the easiest one to prevent. Run the disposal for a few seconds before you start the dishwasher, so its water has a clear path out.

Did a New Garbage Disposal Stop the Dishwasher From Draining?

If your dishwasher won't drain after replacing the garbage disposal, the knockout plug is the most likely cause. New disposals come with a small plastic plug sealed inside the dishwasher inlet, and it has to be knocked out before any water can pass through.

First, unplug the disposal or turn it off at the breaker. Then loosen the clamp, slide the dishwasher hose off the inlet, and push a pencil into the opening. If it hits something solid, the plug is still there. Tap it out with a screwdriver, then pick the loose piece out of the disposal with pliers, never with your hand.

Sink and Dishwasher Not Draining at the Same Time?

When the sink and dishwasher are not draining, the clog is in your plumbing, not the appliance. A blockage past where the two lines meet slows both down. You may also notice the dishwasher not draining and the sink backing up with grey water during a cycle.

A plunger or a small drain snake can clear a simple clog. If the water keeps coming back, a GoGeter plumbing pro can clear the line properly and check for anything deeper. So let's see when u should call the pro  

When Should You Call a Pro for a Dishwasher That Won't Drain?

Once you’ve checked the filter, sump, air gap, disposal, and hose, and the water still won’t drain, the problem is most likely a part inside the machine. That’s when a technician makes more sense than another round of DIY, especially when your dishwasher won’t drain water at all.

These signs mean it’s time to call a pro:

1. A hum or total silence during the drain phase, as mentioned in the causes section.
2. An error code that keeps returning after reset.
3. Water leaking out from under the dishwasher.
4. A running, burning smell.

If you notice a burning smell, turn the dishwasher off at the breaker and leave it off until someone checks it. Here’s a rough idea of what common drain repairs cost.

These are national estimates, so your price will depend on where you live, your dishwasher’s model, and local parts and labor rates.

How Much Does It Cost to Fix a Dishwasher That Won't Drain?

Most dishwasher repairs fall between $160 and $300. A clogged filter costs far less to sort out, while a new pump or motor sits at the top of the range. Getting a quote before any work starts makes it easier to plan. You can compare local appliance repair pros on GoGetEr and book one who works on your brand.

Before you pick up the phone, here’s a quick recap of where to start.

Ready to Fix It Yourself or Call a Pro?

A dishwasher not draining usually comes down to something simple. Start with the filter and sump, then check the air gap, the garbage disposal and the drain hose, in that order.

Most homeowners find the problem somewhere in those first few steps. If all of those are clear and the water still won’t go down, it’s time to book a pro.

A technician can safely check the pump and other parts inside, and you can find one through GoGeter’s appliance repair services. You don’t have to put up with a tub full of dirty water. For quick answers to common questions, head to the FAQ section below.