Dishwasher Not Draining — How to Fix Standing Water

You open the dishwasher expecting clean dishes and find a pool of murky water at the bottom. A dishwasher that won’t drain is gross, but it’s also one of the more fixable appliance problems. Most causes are clogs you can clear yourself.

Before You Start

Check the garbage disposal first. If your dishwasher drains through your disposal (most do), a clogged or jammed disposal can back up into the dishwasher.

• Run the disposal with running water for 30 seconds
• If you just installed a new disposal, make sure the knockout plug was removed from the dishwasher inlet

This solves the problem about 20% of the time.

Most Likely Causes

1. Clogged Filter — Check This First

Modern dishwashers have a filter at the bottom that catches food debris. If it’s clogged, water can’t drain.

Location: Usually at the bottom center or back of the dishwasher tub. It may twist out or pull straight up.

The Fix:

1. Remove the bottom rack
2. Locate the filter (consult your manual if needed)
3. Twist or pull to remove
4. Rinse under hot water
5. Use a soft brush to remove stuck debris
6. Reinstall

Time: 10 minutes. Cost: Free.

Tip: Clean your filter monthly if you don’t pre-rinse dishes. Every 3 months if you do.

2. Drain Hose Clog or Kink

The drain hose runs from the dishwasher to either the garbage disposal or the drain under the sink. Kinks block flow. Clogs from grease and food buildup block flow.

The Fix:

1. Pull the dishwasher out slightly or access under the sink
2. Check the hose for kinks — straighten any you find
3. Disconnect the hose (have towels ready) and check for clogs
4. Flush with hot water or use a long brush to clear debris
5. Reconnect and test

Time: 30-45 minutes. Cost: Free (unless hose needs replacing, ~$15-25).

3. Clogged Air Gap or High Loop

If your dishwasher has an air gap (that little cylinder on the sink top), it can clog. If there’s no air gap, there should be a high loop in the drain hose — if this sags, dirty water can back-siphon.

Air Gap Fix:

1. Remove the air gap cap
2. Clean out any debris inside
3. Check that water can flow freely through

High Loop Fix: Make sure the drain hose rises to near the underside of the counter before going down to the drain connection.

4. Clogged Drain Pump

The drain pump pushes water out. If debris gets past the filter and into the pump, it can jam.

The Fix:

1. Remove the filter and filter housing
2. Look for debris in the pump area (you may see a cover you can remove)
3. Remove any visible debris (broken glass, food, etc.)
4. Spin the pump impeller by hand — it should move freely

If the pump won’t spin or sounds like it’s running but not pumping, the pump may be failed (see below).

5. Failed Drain Pump

If the pump motor has burned out, you won’t hear it running during the drain cycle.

Signs:

• No humming/running sound during drain
• Pump spins freely but no water moves
• Pump makes grinding noises

The Fix: Pump replacement. This is moderate DIY (involves accessing the bottom of the dishwasher and dealing with electrical connections) or a service call.

Cost: $100-200 for the pump, plus installation if not DIY.

Step-by-Step Troubleshooting

1. Run the garbage disposal — clear any backup there first
2. Scoop out standing water — use a cup and towels or wet/dry vac
3. Remove and clean the filter — at the bottom of the tub
4. Check for debris in the drain area — under the filter
5. Inspect the drain hose — look for kinks, check for clogs
6. Clean the air gap (if present) — remove cap and clear debris
7. Run a test cycle — empty dishwasher, short cycle
8. Still not draining? — drain pump may be failed

Can You Fix It Yourself?

✅ DIY-Friendly:

• Clean the filter
• Clear drain hose clogs or kinks
• Clean the air gap
• Remove debris from drain area
• Run the garbage disposal

🛑 Call a Pro If:

• Drain pump is failed
• You can’t access the drain hose
• Problem persists after all cleaning
• Dishwasher is making unusual sounds
• Water is backing up into the sink when dishwasher runs

Prevent Future Drainage Problems

• Scrape dishes before loading — you don’t need to pre-wash, but scrape off big chunks
• Clean the filter monthly — especially if you don’t scrape dishes
• Run hot water in the sink before starting — dishwashers work better with hot water from the start
• Don’t overload — water needs to circulate
• Run the dishwasher regularly — sitting unused leads to dried-on gunk in the drain

What a Pro Will Do

Service call ($75-150):

• Diagnose the issue
• Clear clogs in places you can’t reach
• Test the drain pump

Common repairs:

• Drain hose replacement: $100-150
• Drain pump replacement: $200-350
• Control board replacement: $200-400

The Bottom Line

Nine times out of ten, a dishwasher that won’t drain has a clogged filter or a backed-up garbage disposal. Clean the filter, run the disposal, check the drain hose for kinks — that covers most cases.

If you’ve done all that and there’s still standing water, you’re looking at a pump issue or a clog deep in the system. At that point, a service call makes sense.