Dishwasher Not Draining? How to Fix Standing Water Step by Step

A dishwasher that leaves dirty water sitting in the bottom after a cycle is one of the most common kitchen problems, and it shouldn't be ignored. Standing water smells, breeds bacteria and can point to a clog that will soon back up your kitchen sink too. In many cases you can fix it yourself in under an hour. Here's why your dishwasher isn't draining, how to fix it step by step, and when the real problem is your kitchen drain.

Quick Answer

If your dishwasher isn't draining, turn off the power, scoop out the standing water, and clean the filter at the bottom of the tub. Then check that the drain hose isn't kinked or clogged, clear the air gap on the sink, and run the garbage disposal. If you just installed a new disposal, the knockout plug inside the dishwasher inlet probably needs to be removed. If the kitchen sink is backing up too, the clog is in the drain line, not the dishwasher.

Why Is My Dishwasher Not Draining?

• Interrupted cycle. If the last cycle was stopped partway, water may simply be left over. Run a short rinse cycle first.
• Dirty or clogged filter. Food, labels and grease collect in the filter at the bottom of the tub.
• Clogged or kinked drain hose. Food bits can block the hose, and it often gets crushed when the dishwasher is pushed back into place.
• Clogged garbage disposal. Most dishwashers drain through the disposal, so a clogged disposal stops the dishwasher too.
• Garbage disposal knockout plug. New disposals come with a plastic plug in the dishwasher inlet. If it isn't knocked out during installation, the dishwasher can't drain at all.
• Clogged air gap. The small cylinder on the sink deck can fill with debris.
• No high loop. If the drain hose isn't looped up under the counter (or connected to an air gap), dirty sink water can flow back into the dishwasher.
• Detergent buildup. Too much detergent, or the wrong type, can leave residue that slows drainage.
• A failing drain pump. If the pump is jammed or worn out, water won't leave the tub.
• A clogged kitchen drain line. Grease and food buildup in the pipe past the sink trap stops both the sink and the dishwasher from draining.

Safety First

• Switch off the circuit breaker for the dishwasher and unplug it if you can reach the plug.
• Be careful around electrical components inside the dishwasher, especially when there's standing water.
• Scoop out the water with a cup or ladle into the sink, then dry the bottom with towels.
• Wear gloves to protect your hands from strong detergent, broken glass and knives.
• If any step feels beyond your comfort level, stop and call a professional.

9 Ways to Fix a Dishwasher That Won't Drain

1. Run the Garbage Disposal

If your dishwasher drains through the disposal, run the disposal with cold water for about 30 seconds to clear any food blocking the connection, then run a short dishwasher cycle.

2. Check the Disposal Knockout Plug

If the problem started right after a new garbage disposal was installed, disconnect the dishwasher drain hose from the disposal and look into the inlet. If it's sealed with plastic, tap it out with a screwdriver and hammer, then fish the plug out of the disposal before running it. Here's more on clearing a clogged garbage disposal.

3. Check for Obstructions

Look inside the tub and remove food scraps, paper, labels or small items around the drain area. Take out the bottom rack and check the sump for anything wedged in place.

4. Clean or Replace the Filter

The filter usually sits at the bottom of the tub under the lower spray arm. Twist it out (check your owner's manual), rinse it under hot water with a soft brush, and put it back. Clean it every month or two to prevent repeat problems.

5. Clean the Air Gap

If you have an air gap, the small cylinder on the sink deck, pull off the cover and clean out any debris with a brush or paper towel.

6. Check the Drain Hose

Pull the dishwasher out and make sure the hose isn't kinked, crushed or clogged. Disconnect it and flush it with water, or clear it with a long flexible brush. Make sure the hose rises in a high loop, secured to the underside of the counter, or connects through an air gap before it drops to the drain. Local code may require an air gap.

7. Check the Drain Pump

Many newer dishwashers use a drain pump instead of a valve. With the power off, remove the filter and check the pump cover for broken glass, seeds or labels jamming the impeller. If you hear a hum but no water moves, the pump may need replacing, which is a job for an appliance technician.

8. Use Baking Soda and Vinegar for Light Buildup

Pour a cup of baking soda and a cup of white vinegar into the basin at the bottom of the dishwasher (with the filter in place), wait 15–20 minutes, then pour hot water through and run a rinse cycle. This only helps with light buildup. It won't clear a clogged drain line.

9. Clean the Spray Arms

Twist off the spray arms, rinse them in the sink and clear any clogged holes with a toothpick. Clean arms help the dishwasher wash and drain properly.

When the Problem Is Your Kitchen Drain, Not the Dishwasher

Your dishwasher drains into the same pipe as your kitchen sink. If the sink is slow, gurgles or fills with water when the dishwasher runs, the clog is in the kitchen drain line. Usually it's grease and food that have hardened inside the pipe. A plunger on the sink (with the dishwasher hose clamped) can sometimes clear it, but grease-packed lines usually need professional kitchen drain cleaning in Reno, or hydro jetting to scour the pipe walls clean. To keep it from coming back, keep fat, oil and grease out of the drain.

Plumber or Appliance Repair?

Call a plumber when the problem is in the plumbing: a clogged kitchen drain line, the disposal connection, the air gap, a leaking drain hose connection, or installation issues. Call an appliance technician when the dishwasher shows an error code, the pump or motor hums but won't run, or the control board fails. If you're not sure, start with the drain. If the sink drains normally and the hose is clear, the problem is likely inside the appliance.

Frequently Asked Questions

Why is there standing water in my dishwasher?

The most common causes are a clogged filter, a kinked or blocked drain hose, a clogged air gap, a disposal knockout plug that was never removed, or a clogged kitchen drain line.

Is a little water in the bottom of a dishwasher normal?

A small amount around the filter area can be normal on some models. More than about an inch, or dirty water sitting after a full cycle, means it isn't draining properly.

Can a clogged garbage disposal stop a dishwasher from draining?

Yes. Most dishwashers drain through the disposal, so a clogged disposal or a knockout plug that's still in place will stop the dishwasher from draining.

Should I call a plumber or an appliance repair technician?

Call a plumber for drain line, disposal, air gap or installation problems. Call an appliance technician for error codes, pump or motor failures and control issues.

Kitchen Drain Backing Up? Call Easy Rooter Plumbing

If the dishwasher still won't drain, or the sink is backing up too, Easy Rooter Plumbing can clear the kitchen line and fix the disposal or drain connection, and we've done it for Reno and Sparks homeowners since 1979. Installing a new unit? We also handle dishwasher installation. Call (775) 331-3636.