How to Clear a Blocked Dishwasher Drain


If your dishwasher backs up and leaves standing water in the bottom, it's likely due to a blocked drain. Clearing a clogged dishwasher drain is a common plumbing issue, but it's usually a straightforward fix. This guide will help you get your dishwasher draining properly again.

Why is my dishwasher backing up into the drain?

There are a few common reasons why a dishwasher drain can become blocked:

Food Debris and Grease Buildup

Over time, small food particles, grease, and other gunk can accumulate in the dishwasher drain, causing a clog.

Mineral Deposits

Hard water can leave behind mineral deposits that block the drain.

Mechanical Issues

Problems with the dishwasher's drain pump or hose can also lead to a clogged drain.

What You Need

To clear a blocked dishwasher drain, you'll need a few basic tools and products:


You can use a standard cup-style plunger to unclog sinks and drains.

Why It's Important: The plunger creates suction to help dislodge and clear the clog.

How to Use: Place the plunger over the dishwasher's drain opening and plunge up and down firmly several times to create suction.

Drain Snake or Auger

It’s a flexible, long metal cable resembling a corkscrew that you can introduce into the drain to clear blockages.

Why It's Important: It can go into hard-to-reach areas that other tools may not easily reach.

How to Use: Carefully insert the end of the drain snake into the dishwasher's drain opening and slowly turn the handle to feed the cable into the drain. Rotate the snake to break the clog, then pull it back out.

Baking Soda and Vinegar

Common household ingredients that can help dissolve and flush out clogs.

Why It’s Important: Baking soda and vinegar can have a chemical reaction that aids in the breakdown of organic matter down the drain.

How to Use: Pour the mixture down the dishwasher's drain. After it has been sitting for 15 to 20 minutes, use hot water to clear the drain.

Dishwasher Cleaner or Descaler

Specialised products designed to clean and maintain dishwasher drains.

Why It's Important: These cleaners can help remove built-up grime and mineral deposits.

How to Use: Follow the instructions on the product packaging. Typically, this involves pouring the cleaner into the dishwasher and running a cycle.

Gloves and Protective Eyewear

Wear gloves and safety glasses to protect your hands and eyes when working on the drain.

Why It's Important: Handling plumbing issues can be messy, and it's important to protect yourself.

How to Use: Wear gloves and glasses while working on the dishwasher drain.

Steps on How to Clear a Blocked Dishwasher Drain

1. Unplug the dishwasher or shut off the appliance's circuit breaker.

2. Remove any standing water from the dishwasher by bailing it out with a cup or small container.

3. Use the plunger to try and dislodge the clog. Plunge the drain opening firmly several times.

4. If the plunger is ineffective, use a drill or drain snake to clear the obstruction. Place the snake's tip inside the drain, rotate the handle to feed it, and remove it.

5. Try the baking soda and vinegar by pouring the ingredients down the drain and letting them sit for 15-20 minutes before flushing with hot water.

6. If the clog persists, use a dishwasher cleaner or descaler product according to the instructions on the packaging.

7. Once the drain is clear, run a full dishwasher cycle to ensure the water drains properly.


1. If the clog is deep in the drain or you're unable to clear it, you may need to call a professional plumber for assistance.

2. Avoid harsh chemical drain cleaners, which can damage the dishwasher's components.

3. Be cautious when using the drain snake, as it can scratch or damage the dishwasher's interior.

Additional Tips

1. Regularly clean your dishwasher's filter to help prevent future clogs.

2. Consider installing a dishwasher air gap or high loop to help prevent backflow and clogs.

3. If you removed the clog but the dishwasher is still not draining correctly, there might be a problem with the drain pump or hose that a licensed professional must fix.

Frequently Asked Questions About Blocked Dishwasher Drain

Why is there standing water at the bottom of my dishwasher?

Stagnant water inside the dishwasher is usually a sign of a clogged drain. The water cannot drain properly, accumulating in the appliance's bottom.

Can you put a drain unblocker in a dishwasher?

Using harsh chemical drain cleaners in a dishwasher is not recommended in general. After all, they can damage the appliance's components. Instead, use the baking soda and vinegar method or a dishwasher-safe cleaner or descaler.

Is it safe to run a dishwasher with standing water in it?

No, running a dishwasher with standing water in the bottom is unsafe. The water can damage the dishwasher's internal components and potentially lead to further issues. Always clear the standing water before running a cycle.

Get Expert Help When You Need It

If you've tried all the steps to clear a blocked dishwasher drain and are still experiencing issues, it's time to call in the professionals. All Needs Plumbing offers $0 callout fees, $150 off hot water systems, and a 15% discount for seniors. Our 24/7 same-day services ensure we can get your dishwasher draining properly quickly. Contact us today to schedule an appointment and get your kitchen back in order.

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