LG Dishwasher Not Draining? (here’s why & what to do)

A pool of water and dirty dishes are not what you expect to find after the dishwasher has finished. If your LG dishwasher isn’t draining it can be worrying. 

But many of the common causes for this issue are easy to solve without involving any costly repairs. In this article we look at the likely causes of your LG dishwasher failing to drain and offer solutions for these problems.

Why Is The LG Dishwasher Failing To Drain?

This is a relatively common problem in all dishwashers including LG dishwashers. Before we get into the possible reasons why your LG dishwasher is not draining, let’s start with advice on how to clear the standing water in the tub of your appliance.

There are a few ways to accomplish this which include;

  • Scooping The Water Out With A Jug
    To scoop the water out using a jug we recommend laying a towel on the floor to collect any spillage first. Then using the jug, scoop the water from the tub of the dishwasher. Any small remaining puddles can be soaked up using a towel.
  • Vacuuming The Water Out Using A Wet/Dry Vacuum
    Start by putting the wet filter on the vacuum and then turn it on. Using the hose, remove all of the water from the tub.

Which Method Works Best?

If you only have a small amount of water to remove, we recommend using a jug to scoop it out. However, if there is a considerable amount of water in the tub, the wet/dry vacuum is your best option.

What Could Cause The LG Dishwasher To Fail To Drain?

There are several possible reasons why your LG dishwasher is not draining properly (or at all) which include;

Probable CauseSolution
Cycle InterruptedRestart the cycle
Incorrect or excessive amount of detergent usedAlways use the correct type and quantity of detergent
Filter cloggedRemove filter, clean and replace
Drain hose cloggedRemove any blockages from the drain hose
Waste disposal unit cloggedRemove any blockage from the waste disposal unit
Sink drain blockedRemove any blockage
Air gap blockedClean the air gap and remove any blockage
Stuck check valveInspect and replace the check valve if necessary
Faulty drain pumpReplace the drain pump

Let’s take a closer look at each of these issues;

Cycle Interrupted

If the cycle is interrupted for any reason it could cause the LG dishwasher to fail to drain correctly. There might have been a power failure or you might have accidentally interrupted the cycle.

If an interrupted cycle has caused the issue, simply restarting the cycle could solve the problem.

Incorrect Or Excessive Amount Of Detergent Used

dishwasher tablets

This is one of the most common causes of a dishwasher failing to drain correctly. The detergent used in dishwashers is formulated to produce fewer soap suds.

Using an incorrect detergent can cause too many soap suds to be produced which can impede the drainage process. The same can be true if you have used too much detergent even if it is the type recommended for your appliance.

If you suspect that you have used the wrong type of detergent or too much detergent, try running a rinse and drain cycle to clear any excess. Once the problem has been solved, remember to always use the correct type of detergent in the correct quantity in future to prevent this problem happening again.

Filter Clogged

The dishwasher’s filter traps food particles and other debris during the wash and rinse cycles preventing those particles from returning to the dishes. Over a period of time, the filter can become clogged with food particles and other debris which will impede the water from draining out of the tub.

The filter is typically located on the bottom of the tub and can be accessed by removing the lower rack. Then follow the directional arrows to undo the filter before removing it from its housing.

Clean the filter under running water to get rid of all of the food and other debris. Any stubborn particles can be removed after soaking the filter in warm soapy water using a toothbrush.

If some particles still remain, you can remove them by soaking the filter in a white vinegar/ water solution.

Pump Impeller

Whilst the filter is removed, you can check the drain pump impeller which is situated just below the filter housing. Check the impeller for any pieces of broken crockery or food particles which could be impeding the impeller from doing its job.

Drain Hose Clogged

All of the waste water from the dishwasher travels through the drain hose. If the drain hose has a twist or is kinked it could cause a blockage which would impede the waste water’s flow from the dishwasher.

It is also possible that pieces of food or broken crockery could eventually find their way into the drain hose and cause it to clog. You may have to remove the drain hose from the machine if you suspect it is blocked.

Once removed, you can push a plumber’s snake through the hose to remove any blockages.

If you don’t want to disconnect the drain hose, you could try pouring 1 cup of bicarbonate of soda followed by 1 cup of white vinegar into the tub and wait for 30 minutes or so for this mixture to do its job.

If the standing water has gone, the mixture has worked, and you should run a hot wash to remove any remaining gunk from the tub. If the water remains, you may need to use a plumber’s snake.

Waste Disposal Unit Clogged

If your dishwasher is connected to your waste disposal unit, you will need to check that the blockage isn’t in the unit. The easiest way to check the waste disposal unit is to run it for around 30 seconds or so and see if this clears any blockages.

If not you should consult the user manual as many waste disposal units can be operated manually using an allen key. All you need to do is locate the socket, insert the correct allen key and turn it backwards and forwards until you feel reduced resistance.

Sink Drain Blocked

kitchen sink

In many cases, the dishwasher is connected to the drain pipe under the sink. If this drain pipe has a blockage, it will prevent the waste water from leaving the dishwasher.

To solve this, you’ll need to check the drain pipe and remove any blockages.

Air Gap Blocked

Some drain hoses are connected to an air gap which prevents any dirty water from re-entering the dishwasher. Over a long period of time, the air gap can become blocked with food particles, fat and/or grease.

Once the air gap is blocked, it will prevent the waste water from the dishwasher from draining away. You can check the air gap by removing the cover and cap and then inspect it for any likely blockage.

If there is anything blocking the tube it can often be removed using a pair of tweezers before cleaning the tube using a tube brush. If this all sounds beyond your comfort zone, we recommend getting a plumber to sort this for you.

Stuck Check Valve

Dishwashers have a small device fitted that allows water to leave the appliance but prevents it from returning. This is designed to prevent dirty water from backwashing into the appliance and making the dishes dirty again.

In some cases, the check valve can become stuck which prevents dirty water from leaving the appliance. In others it can break completely allowing dirty water back in.

You will need to get the check valve inspected and replaced if necessary.

Faulty Drain Pump

A faulty or defective drain pump could also cause the LG dishwasher to fail to drain properly. The pump can become clogged with food, grease or pieces of broken crockery.

Checking the drain pump can be difficult because it involves dismantling panels from the dishwasher as well as removing hoses etc. Unless you are a competent DIYer we recommend leaving this to an expert.

Ways To Prevent The Dishwasher Failing To Drain 

Dishes

That old saying prevention is better than cure is never more accurate than when applied to dishwashers. There are a few things you can do to prevent the dishwasher failing to drain which include;

  • Always scrape dishes before stacking them in the dishwasher
  • Ensure the dishes are stacked properly in the racks
  • Always use the correct detergent in the right quantity
  • Run a hot service wash every month
  • Clean the filter every month
  • Inspect the hoses for any twists regularly

SEE ALSO: LG Dishwasher Won’t Start But Has Power? Here’s why & what to do

Frequently Asked Questions

What could cause a LG dishwasher to fail to drain?

There are several things that could cause a LG dishwasher to fail to drain including; an interrupted cycle, using an incorrect or too much detergent, clogged filter, clogged drain hose, clogged waste disposal unit, clogged sink drain, blocked air gap, stuck check valve or a faulty drain pump.

What preventive measures can be taken to avoid dishwasher drainage issues?

To prevent the dishwasher failing to drain you can scrape dishes before loading them, stack dishes properly in the racks, use the correct detergent in the right quantity, run a hot service wash every month, and clean the filter regularly. Additionally, inspect the hoses for any twists regularly.

How often should you run a hot service wash and clean the filter to prevent drainage issues in the LG dishwasher?

It is recommended to run a hot service wash and clean the filter every month to ensure proper functioning and prevent drainage issues.

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