Dishwasher Not Draining? What to Check First and 6 causes

Dishwasher not draining? Check the drain hose first and then follow this guide to troubleshoot for six other causes. Whether you decide to hire an expert or to repair it yourself, the first thing is to check the drainage system of your dishwasher. 

Although there are different models of dishwashers, the drainage system functions the same way and possibly will have similar solutions. One simple thing to check first is the drain hose. 

If the hose is connected properly, it will be attached to the drain pipes under the kitchen sink. Remove the hose and gently clean the elbow joint to make sure nothing is stuck in there. An obstructed drain hose will cause water not to flow.

If the drain hose is not clogged, make sure it is not kinked or damaged. Replacement hoses can easily be purchased off Amazon or your manufacturer’s website.

Now that you’ve checked the drain pipe, let’s explore six other possible causes for a dishwasher not draining. Problems could include: a defective drain pump, clogged Garbage disposal, water back flow, obstructed drain hoses, drain valve issues, or a problem with your dishwasher cycle timer.

In this article, we will show why your dishwasher is not draining properly and ways to fix it.

Dishwasher Not draining? 6 other Possible causes

Defective Drain Pump

The drain pump is always one of the last component parts of your dishwasher to get faulty. Typically, the drain pump utilizes an impeller that helps in draining water out of your dishwasher. 

However, once the impeller is faulty due to a number of reasons, water in the dishwasher remains undisposed.

So, what are the reasons your drain pump will be helpless while your dishwasher won’t drain? 

The first problem may be that some foreign object, usually pieces of broken glass, has blocked the way of the pump. One of the signs that inform you that the pump has been clogged is a sort of humming sound coming from the motor as soon as a cycle begins.

Clogged Garbage disposal

You observe that your whirlpool dishwasher is not draining at the end of the cycle, then try to check out for garbage disposal connection. 

A garbage disposal may cause your dishwasher not to drain residual water. 

The fault is always traced to issues during installation. It could also be that your disposer is clogged.

Inside the garbage disposal’s drain tube is a solid plug that usually blocks drainage. 

How to fix:

• Check if the plug is in order or the garbage disposal has clogs by removing it.
• Remove the drain hose and sanitize the joint of the disposal and drain hose.
• Check your food chopper if the food particles are much larger than what you can manually remove.

Water back flow From The Sink

Have you noticed that sometimes your dishwasher drains, but after a while, you find water remains at the bottom of the machine? Retained water in the base of your dishwasher is not good. It can cause smells and water spots in the tub.

This is often caused by a faulty check ball or check valve flapper. It is a small plastic ball in the check valve that prevents back flow. There is a possibility that a stuck ball can restrict the free flow of water at the check valve.

Obstructed drain hose

Food debris clogging the drain hose is the most common cause of this issue.

The drain hose is the part of your dishwasher that connects the machine to the garbage disposal compartment under your kitchen sink. (Or to the sink drain if no disposal)

A restriction in the drainage, due to food particles or a kink in the line, will prevent the dishwasher from draining properly.

How to fix:

If the line has developed a kink, simply untwist or replace the drain hose.

However, if the food chopper has accumulated food debris, remove the drain hose from the pump and clean it. You can run water through it in the sink. In the case of accumulation of food debris, the permanent solution is to fix the food chopper.

Defective Drain valves 

If you check near the motor of your dishwasher, you will find drain valves. The drain valves allow wastewater to drain out of your dishwasher, preventing it from back flow onto your clean dishes. Faulty valves allow back flow of dirty water back into the dishwasher.

Sometimes the valves are clogged by food debris, obstructing water from exiting the dishwasher. This can also cause a bad smell from the used, undisposed water.

If you have a smell that cannot be fixed by cleaning the dishwasher, you’ll need to check the drain valves. 

How to fix:

First, remove the valve to check what it needs. Clean off the dirt in it. But if the valve is bad, try to replace it as a faulty valve cannot be fixed. 

How do you check if your machine’s valve is defected? Remove the drain hose, fill it with water and try to drain.

While you’re trying to trap the water from escaping, you will see the valve opening. And after draining, the valve will not close again.

malfunctioned Dishwasher timer

There is another reason why your dishwasher won’t drain. 

If you check the control panel of your old machine, you find the timer. This part helps the dishwasher control the motor and also the drain solenoid. When this timer is faulty, your dishwasher will not drain wastewater.

How to fix:

How do you know that the timer is faulty? Different Frigidaire dishwashers are built with unique wiring plan.

Check these schematics to understand the exact timer that works for your own Frigidaire dishwasher.

The way to go is to check if the current gets in the timer. Once the timer fails to indicate any current out, then the timer is defective.

And the only way is to replace a bad timer. However, if the timer signals current out, then it is functioning.

Trace the wire until you get to the point where there is current break. Try to replace the wires if there is any fault detected. 

How to fix a clogged Drain pump?

Fixing a dishwasher clogged by foreign object through the drain pump is quite simple. Take the following steps:

• First disconnect the feeder hose, the anti-flood switch and any other connection that could get damaged in the process of moving the machine around.
• Unscrew the base plate of your dishwasher, then the drain pump.
• Carefully turn and pull the drain pump out. Any sign of resistance when pulling may be due to a screw holding the pump down.
• Check and scrap any food debris clogging the impeller. 
• Check if the impeller or motor is properly rotating, not running or running in the wrong direction by trying it out with your finger. Any of these will be the cause of why your dishwasher won’t drain.  
• If the motor is not rotating or rotating wrongly, then use a meter to check if the circuit gets to the terminals. If your drain pump is not working, then be sure that it is either there is a problem with your machine’s motor winding, or the motor has seized.
• Replace the seized motor with the right one. 

How to fix Drain pump check valve:

The fix is simple. Simply, use a screwdriver to free the ball and spray some lubricant to allow free flow of the check valve. 

How to manually drain a dishwasher?

In addition to the drainage problems discussed earlier, a clog or leftover water can cause your dishwasher to produce fishy odors. 

If your dishwasher isn’t draining water, fixing it might be one of the quick and easy issues to deal with manually. 

But you will need to do some troubleshooting to know what the problem is. Start your troubleshooting to know if the dishwasher’s filter is clogged and try to clean them.

However, that does not solve the problem; you’ll need to check the drain hose and valve for clogs 

Take the following steps to do proper manual cleaning of your dishwasher:

The process starts with removing the dishes from the dishwasher before placing them in the sink. Turn off the power connection with dishwasher as well as water flow into the machine. You disconnect the power flow into the dishwasher by shutting off the circuit that connects to the machine.

As to water flow, turn off the water supply by turning off the copper line or braided stainless steel-enabled water line.

Then remove the water with containers and towels or just follow steps in this video

Can you put a drain cleaner in a dishwasher?

It is not advisable to put drain cleaner into the dishwasher for a number of reasons.

Although the drain hose in your dishwasher can help clear off particles of food left on your dishes, the part can also potentially clog up, rendering your machine inefficient. 

Using a drain cleaner is also not the best way to clear this clog caused by drain hose.

There are attendant health risk that comes with using drain cleaner to unclog the dishwasher drain hose. Never try to put a drain cleaner in your dishwasher. It is risky!

One is that drain cleaner could potentially damage the rubber or plastic inside of your dishwasher. Some of the commercial drain cleaners out there contain toxic chemicals. 

And when you mix a drain cleaner into your dishwasher, the residue left from the cleaning agent may be left in the machine, constituting health risks to your dishes during future wash cycles. 

The drain cleaner residue is also harmful to your health.

The drain cleaner could also damage the drain hose or some other important parts of the dishwasher. It could also cause leakages and other mechanical problems to your machine.

What alternative methods can you use to manually drain your dishwasher?

The next time you observe your dishwasher is not draining, clean it following this method. 

Mix baking soda with white vinegar and apply it on your dishwasher to dissolve minor drain clogs.

How to use it:

• Disconnect the dishwasher from the power source
• Locate the drain connection to unscrew the nuts holding the connection in place.
• Loose the screws that hold the dishwasher and then move the machine.
• Remove the drain hose but try to place a bucket under it to catch any liquid that escapes from the dishwasher.
• Pour the mixture of baking soda and vinegar.
• Allow the blend to stay on the clog for some time before running your dishwasher through a normal cycle in order to remove any residue. 
• Do this once in a month to help to clean the dishwasher. 

Conclusion

Good maintenance to your dishwasher is the best way to have a long lasting use of the machine. Preventive measures, like keeping hoses and filters clean, are the best way to prevent damage to the more expensive components of the appliance. You can also save yourself the expense of paying a technician to troubleshoot for you.