Why Doesn’t My Dishwasher Drain?

If your dishwasher isn’t draining properly, several factors could be causing the issue. A clogged drain hose, often blocked by food particles, soap buildup, or mineral deposits, can restrict water flow. A dirty or obstructed dishwasher filter can also prevent proper drainage, making regular cleaning essential. 

In some cases, a faulty drain pump—whether due to wear, electrical malfunctions, or blockages—may be the culprit. Mechanical components like the solenoid valve or float switch can also fail, disrupting the draining process. Additionally, loose or clogged connections to the air gap or garbage disposal can contribute to drainage problems.

By inspecting and addressing these common issues, you can restore your dishwasher’s functionality and prevent further complications.

Clogged Drain Hose

A clogged dishwasher drain hose can stop water from draining. This happens when there is foreign objects or food bits, soap, or hard water minerals build up inside the hose. When water can’t flow out, it might sit at the bottom of the dishwasher, which can be messy and make the dishwasher work poorly.

The drain hose is a bendy plastic tube that connects the dishwasher to your home’s plumbing. Over time, stuff like food scraps and soap can stick to the inside, making it hard for water to pass through.

To fix a clogged drain hose, first, unplug the dishwasher to stay safe. Take off the hose and check inside for stuck stuff. You can use water pressure or a long brush to push out the junk. Sometimes, a mix of vinegar and baking soda can help clean out mineral gunk.

Make sure to put the hose back right so water can flow easily. Regular cleaning can stop these problems before they start.

Faulty Drain Pump

A common problem in dishwashers is when the drain pump doesn’t work right. This pump is important because it helps get rid of dirty water after the dishwasher runs. If the pump is broken, water might stay in the bottom of the dishwasher, which can cause poor cleaning and might harm the machine.

The drain pump can stop working for several reasons. It might wear out over time. Electrical problems, like a motor that burns out or bad wires, can also cause issues. Sometimes, small things like food bits can block the pump.

To find out if the drain pump is broken, you can look for visible damage, check the electrical connections, or see if anything is stuck in it. If it’s broken, it’s usually best to have a professional replace it to make sure it works correctly.

Blocked Filter

A clogged filter can stop your dishwasher from draining water well, causing water to build up and dishes not to get clean. The filter catches food bits and other stuff so they don’t clog the drain. When the filter gets full, the water can’t flow through it easily, and this can cause problems with draining.

The drain filter is usually at the bottom of the dishwasher under the lower dish rack. It’s made of a net-like material that lets water pass but catches debris. If the filter is clogged, dirty water might keep washing over the dishes, making them not as clean.

According to Consumer Reports, dishwashers with self-cleaning filters break down food scraps automatically, requiring little maintenance. However, manual filters need regular cleaning to prevent clogs and ensure optimal performance. Most manufacturers recommend cleaning the filter every two to three months, though frequent dishwasher use may require more frequent maintenance. A clear sign it’s time for a cleaning is when there are leftover food particles on dishes after a wash cycle.

To clean the dirty filter, locate it beneath the spray arms and remove it—some models have multiple parts that can be separated for deeper cleaning. Rinse it under running water to remove debris, and use a sponge, soft brush, or toothbrush with warm, soapy water for stubborn food buildup. Avoid using wire brushes or scouring pads, as they can damage the filter. Always refer to your appliance manual or the manufacturer’s website for model-specific instructions.

Air Gap Issues

Air gap problems can stop a dishwasher from draining properly. This usually happens because something is blocking the air gap device, which helps keep wastewater flowing out of the dishwasher.

The air gap is found on the sink or countertop near the faucet. Its job is to stop dirty water from going back into the dishwasher by letting air in, which breaks any suction that might pull water the wrong way.

If the air gap gets clogged, water might stay at the bottom of the dishwasher. This blockage can happen because of things like food bits or mineral build-up inside the air gap or the hoses connected to it.

Checking and cleaning the air gap regularly is important to keep it working well.

To fix air gap blockage, first, take off the air gap cover and look for blockages. You can clean it with a small brush or a pipe cleaner to get rid of any debris.

If that doesn’t solve the problem, check the hoses to make sure they are not twisted or clogged.

Garbage Disposal Connection

A bad garbage disposal connection can stop your dishwasher from draining right. This happens if the dishwasher hose isn’t hooked up right to the garbage disposal. The hose needs to be tightly attached to the right spot on the disposal. If it’s loose or not lined up, it can cause leaks or block water, making it hard for the dishwasher to drain.

Also, when putting in a new garbage disposal, you have to take out the knockout plug from the disposal’s inlet. If you don’t, it can block the water from leaving the dishwasher. Checking the connection often can help find and fix any blocks or problems.

Food scraps and grease can build up in the disposal, causing clogs that stop the dishwasher from draining. Cleaning the disposal with the right cleaners can stop this build-up. Keeping your garbage disposal working well and clear of clogs is important for your dishwasher to drain properly.

Malfunctioning Check Valve

A check valve in a dishwasher is important because it stops dirty water from coming back into the machine. It works like a one-way door that lets water out but not back in. If the check valve doesn’t work right, water can collect at the bottom of the dishwasher, causing it to work poorly and possibly leading to water damage.

• Debris Build-Up: Bits of food and other stuff can get stuck and make the valve stay open. This means it can’t stop water from coming back like it should.

• Worn-Out Parts: The valve opens and closes a lot, which can wear it out and make it not seal properly.

• Objects Blocking the Valve: Things like small pieces of glass or plastic can get stuck in the valve, stopping it from working right.

It’s important to regularly check and clean the check valve to keep the dishwasher working well. If you notice any problems, like water not draining, it might be time to look at the check valve.

Replacing it if it’s broken can help keep your dishwasher running smoothly for a long time. Knowing how the check valve works and how to take care of it can help you fix drainage problems.

Improperly Installed Dishwasher

For a dishwasher to work well, it needs to be set up the right way. If not, you might have problems like water not draining. This can happen if the dishwasher isn’t level. When it’s uneven, water can get stuck at the bottom and cause bad smells.

Another thing to check is the drain hose. It needs to have a high loop near the kitchen sink. This loop stops dirty water from coming back into the dishwasher.

Also, make sure the dishwasher is connected tightly to the pipes in your home. If there are leaks, it can mess up the water pressure and stop it from draining right. Checking these things during and after installing the dishwasher can keep it running smoothly and make it last longer.

Kinked Drain Hose

A common problem with dishwashers is a bent drain hose. This can block water from flowing out properly. The drain hose connects the dishwasher to the plumbing system to get rid of dirty water. When the hose gets bent, it slows down the water and stops the dishwasher from draining well. Fixing a bent hose helps the dishwasher work better.

• Look at the Hose: Check the whole hose from the dishwasher to where it connects to the plumbing. Look for bends or twists that might block the water.

• Move the Hose: If you see bends, gently move the hose to make it straight. Make sure it stays in place so it doesn’t bend again.

• Check Inside the Hose: Make sure there isn’t any stuff inside the hose blocking it, like food bits or other debris.

Drain Solenoid Problems

The drain solenoid valve is a key part of a dishwasher that helps control the draining process. It opens and closes the drain valve to let out dirty water. If your dishwasher isn’t draining right, the solenoid might be the problem. Problems can happen because of electrical issues, parts wearing out, or something blocking it.

Signs of solenoid problems and what might cause them:

• Dishwasher not draining: The solenoid coil might have failed.

• Loud humming noise: Something might be blocking the solenoid.

• Erratic drainage behavior: There might be issues with the electrical connections.

A solenoid coil can fail due to too much electricity or long use, making it hard for the valve to open. If there is debris, it can block the solenoid and make a loud noise. Loose or rusted wires can cause the dishwasher to drain irregularly.

Checking and replacing the solenoid, if needed, can fix the problem and make the dishwasher work well again. Understanding these problems can help in fixing solenoid issues effectively.

Float Switch Malfunction

A float switch that doesn’t work right can mess up a dishwasher’s water levels. This can cause problems like not draining properly or spilling over. The float switch is important because it helps control how much water goes in. It tells the water valve when to stop or start filling the dishwasher. If the float switch gets messed up, it might be because of dirt, being out of place, or electrical issues.

Three signs that there might be a problem with the float switch:

• Water Level Problems: If the water level in the dishwasher is all over the place or too high, the float switch might not be sending the right signals. This can lead to drainage problems.

• Water Spills Over: If water spills out of the dishwasher, the float switch might not be stopping the water from coming in. It should tell the valve to close so the water doesn’t overflow.

• Stuck Float: If the float gets stuck, maybe because it’s dirty or broken, it can stop the switch from working right. This can make it hard for the dishwasher to drain.

Fixing float switch problems quickly can get your dishwasher working normally again and stop other issues from happening.

Clogged Sump Basin

A clogged sump basin in a dishwasher can stop it from draining well. The sump basin is like a bowl where water collects before it gets pumped out. It can get clogged with food bits, grease, and mineral deposits, which can cause water to pool at the bottom of the dishwasher.

• Food Bits: These can block the water from draining.

• Grease and Oil: These can make the pump work too hard.

• Mineral Deposits: These can cause water to spill over.

To fix this, clean the sump basin often. Start by taking out any food or junk you can see. Make sure nothing is blocking the drain.

Then, use vinegar and baking soda to wash away mineral deposits. Check the basin for any damage that could make draining worse. Keeping the sump basin clean helps your appliance work well and stops future problems.

Power Supply Issues

To make sure your dishwasher works well, it needs a good power supply. If there’s a problem with the electricity, the dishwasher might not clean dishes right, and water might not drain properly.

• Check the Power Cord: Look at the power cord for any damage like cuts or frayed wires. Damaged wires can stop electricity from getting to the dishwasher. If you see any damage, you need to replace the cord to fix the problem.

• Check the Circuit Breaker: Make sure the circuit breaker hasn’t turned off. Dishwashers need their own circuit to work right. If the breaker is off, turn it back on. If it turns off again, there might be a bigger problem, and you should call an electrician.

• Check the Outlet: Test the outlet with another device to see if it’s working. If the outlet is broken, the dishwasher won’t start or finish its cycle, and water won’t drain properly.

Timer or Control Board Failure

After checking the power supply, the next step is to look at the dishwasher’s timer or control board. These parts are important because they control the dishwasher cycle, including when it drains water. If the timer or control board is broken, the dishwasher might not drain properly, leaving water in the tub.

To check if the timer is working, see if the dishwasher finishes its cycle. If it doesn’t, the timer might be faulty and not start the drainage phase.

The control board is like the brain of the dishwasher. It might have electrical problems or glitches that cause drainage issues. Look for any burned parts or damage on the board.

To find out if the timer or control board is broken, use a multimeter to test the circuits. If you find problems, you might need to replace the broken part.

Check the dishwasher’s manual for the right voltage and resistance levels. This can help make sure the dishwasher works well again.

Incorrect Detergent Usage

Using the wrong type or too much detergent can cause soap to build up and block the dishwasher’s drainage, making water collect at the bottom. Dishwashers need a special type of detergent to work right. If you don’t use the correct ones, it can cause problems like water not draining properly.

• Detergent Type: Always use detergent made for dishwashers. Regular dish soap or other cleaners make too many bubbles, which can block drains. Dishwasher detergent is made to clean off food and rinse away without leaving soap behind.

• Detergent Amount: Using too much detergent leaves soap behind. This soap can cover parts inside the dishwasher, like the drain, and may cause clogs. Follow the amount the maker of the dishwasher model suggests for best results.

• Water Hardness: Water hardness affects how detergent works. Hard water can make it hard for soap to dissolve, causing more buildup. In areas with hard water, you might need to use less detergent or a water softener to stop mineral buildup that can make draining worse.

When to Call a Professional

If your dishwasher keeps having drainage problems even when you use the right detergent and clean it regularly, you might need to call a professional. A licensed plumber can figure out tough issues like broken drain pumps, faulty solenoid valves, or clogged drain hoses that you can’t fix on your own.

Look for signs that mean something is wrong. Strange noises during the drain cycle could mean the motor or impeller is going bad. If water stays at the bottom of the dishwasher after it’s done, there might be a deep blockage or a problem with the check valve, which needs special tools to fix.

Also, if your appliance wasn’t set up right, you might need a professional plumber to check it. The drain hose has to be in the right spot to stop water from coming back in. Complicated plumbing or connections to garbage disposals might also need an expert to make sure everything works smoothly.