If your dishwasher is not draining, the most common causes are a clogged filter, a blocked drain hose or air gap, a jammed drain pump/impeller, or a sink/disposal plumbing restriction. In many cases, it’s a simple blockage you can clear with basic cleaning and inspection.

However, if the dishwasher hums but won’t move water—or it stops mid-cycle with standing water—there may be a mechanical or electrical failure (like a failing drain pump, float switch issue, or control board problem) that needs professional diagnosis.

Why This Problem Happens

Dishwashers drain through a chain of components: the tub filter and sump area, the drain pump, the drain hose (often routed to an air gap or high loop), and finally your sink drain or garbage disposal. A restriction or failure anywhere in that path can leave water behind.

1) Clogged filter or sump blockage

• What it is: Food particles, labels, glass fragments, or grease buildup blocking the dishwasher filter or sump (the low point where water collects).
• Why it happens: Infrequent filter cleaning, heavy soils, or running cycles with poor pre-rinsing habits.
• How serious: Usually low—often the #1 DIY fix.
• DIY or mechanical: Typically DIY.

2) Drain hose restriction, kink, or improper routing

• What it is: A kinked hose, grease clog, or backflow caused by missing/incorrect “high loop” installation.
• Why it happens: Hose gets pinched during installation, debris accumulates, or plumbing changes alter routing.
• How serious: Moderate—can cause repeated non-drain events and odors.
• DIY or mechanical: Often DIY if accessible; sometimes requires a technician due to tight cabinet space.

3) Clogged air gap (if your setup has one)

• What it is: A small fitting on the sink/ countertop that prevents dirty water from siphoning back into the dishwasher.
• Why it happens: Food debris and grease collect in the air gap chamber.
• How serious: Low to moderate—can stop draining or cause water to spill from the air gap.
• DIY or mechanical: Typically DIY.

4) Garbage disposal knockout plug still in place (new installs)

• What it is: A factory plug inside the disposal’s dishwasher inlet that must be removed when connecting a dishwasher drain hose.
• Why it happens: Dishwasher installed to a disposal that was never prepped for the connection.
• How serious: High impact but easy fix—dishwasher may never drain properly.
• DIY or mechanical: DIY for many homeowners, but proceed carefully.

5) Drain pump, float switch, or control issue

• What it is: The pump can seize, the impeller can jam, wiring can fail, the float/float switch can misread water level, or the control board may not send power to drain.
• Why it happens: Wear over time, debris ingestion, electrical faults, or water intrusion.
• How serious: Moderate to high—may require parts replacement.
• DIY or mechanical: Often mechanical/electrical; professional service is recommended.

Why This Problem Should Not Be Ignored

• Secondary damage: Standing water can leak past seals, stress the pump, and damage internal components.
• Odors and bacteria: Stagnant water and trapped food soils create persistent smells and hygiene issues.
• Water damage risk: Overflows or slow leaks can damage cabinets, flooring, and nearby drywall—especially if the unit runs unattended.
• Electrical strain: A struggling pump may overheat, trip protections, or lead to more expensive failure.
• Cost escalation: What starts as a simple clog can turn into a pump replacement if the machine repeatedly tries (and fails) to drain.

Step 1: Try These Fixes First (DIY Section)

Safety first: Turn off power at the breaker (or unplug the dishwasher if accessible). If you’ll be working near the sink disposal, also switch off the disposal power. Keep towels handy—some water spillage is normal.

1) Confirm it’s a drain problem (not leftover rinse water)

1. Open the dishwasher after a cycle ends.
2. Look for standing water above the filter area (not just a damp sump).
3. If there’s a pool of water, continue below.

Success looks like: Only a small amount of water in the sump area (varies by model) and no pooling across the tub floor.

2) Remove and clean the filter assembly

1. Pull out the bottom rack.
2. Twist and lift the filter (most models have a cylindrical filter plus a flat screen).
3. Rinse under hot water; use a soft brush to remove grease and debris.
4. Check the filter housing for broken glass, labels, or bones.
5. Reinstall the filter securely (a loose filter can cause poor wash and drain performance).

What to look for: Sludge, seeds, glass fragments, or anything that could restrict water flow to the pump.

Success looks like: Filter is visibly clean and seated correctly; drainage improves on the next test cycle.

3) Check the sump area and drain inlet for obstructions

1. With the filter removed, use a flashlight to inspect the sump.
2. Carefully remove debris with gloved fingers or needle-nose pliers.
3. If you see a small cover over the drain inlet, ensure it’s not blocked.

Stop if: You see damaged plastic parts, loose wiring, or you’re unable to safely access debris.

4) Run a quick drain test

1. Restore power.
2. Start a short cycle, then cancel/drain (method varies by brand; many use Cancel/Drain or holding Start for 3 seconds).
3. Listen for the drain pump and watch whether water level drops.

Success looks like: You hear a steady drain sound and the standing water clears.

If not: Continue to hose/air gap checks.

5) Inspect the air gap (if present)

1. Remove the air gap cap (usually twists or pops off).
2. Check for debris inside; rinse and clean.
3. Reinstall and run the drain test again.

Success looks like: No water spills from the air gap and the dishwasher drains normally.

6) Check the sink/disposal connection

1. Look under the sink for the dishwasher drain hose connection (to a disposal or sink tailpiece).
2. Confirm the hose is not kinked, crushed, or sagging excessively.
3. If connected to a garbage disposal and the dishwasher is newly installed (or recently replaced), verify the knockout plug was removed.

How to spot a knockout plug issue: Dishwasher tries to drain, but little/no water reaches the sink plumbing; the unit may have never drained well since installation.

7) Verify the “high loop” to prevent backflow

Many installations require the drain hose to be routed up high (near the underside of the countertop) before it drops to the disposal/tailpiece. This helps prevent sink water from flowing back into the dishwasher.

• What to do: Ensure the hose rises as high as possible under the counter and is secured with a strap/clip.
• What it fixes: Recurring water in the tub after the sink is used.

8) Clear a likely hose clog (only if accessible)

If you can safely access the hose under the sink:

1. Turn off power to the dishwasher.
2. Place a shallow pan/towels under the connection.
3. Loosen the clamp and remove the hose from the disposal/tailpiece.
4. Check for grease/food buildup at the end of the hose and the inlet.
5. Flush the hose with warm water (do not force sharp tools inside that could puncture it).
6. Reconnect securely and test drain.

Success looks like: Strong flow into the sink plumbing during drain, and no standing water remains in the dishwasher.

Step 2: Identifying Mechanical vs Electrical Failure

After cleaning and clearing the drain path, the dishwasher’s behavior can help narrow down what’s wrong.

If it makes a humming noise but doesn’t drain

• Most likely: Drain pump impeller jam, seized pump, or debris in the pump housing.
• What it means: The motor may be getting power but can’t move water.
• Next step: Professional service is often the safest route, especially if pump access requires removing panels and dealing with water lines.

If it is completely silent during the drain phase

• Most likely: Control not sending power, door switch issue, wiring fault, or failed pump motor.
• What it means: Could be electrical or control-related rather than a simple clog.
• Next step: Service call recommended for proper electrical diagnosis.

If it drains slowly or leaves a shallow pool

• Most likely: Partial blockage (filter, hose, air gap), weak pump, or restriction in sink plumbing.
• What it means: Water is moving, but not fast enough.
• Next step: Re-check filter seating, hose routing, and disposal/tailpiece for buildup; consider pump performance if repeats.

If it drains sometimes, but not consistently

• Most likely: Intermittent pump failure, float/float switch sticking, or control issue.
• What it means: Not typical of a single clog—more often a component that’s failing under heat/load.
• Next step: Professional diagnosis to prevent repeated water retention and potential leaks.

Repair Cost Expectations

Dishwasher drain repairs range from simple cleaning to part replacement. Typical costs vary by brand, model, and region, plus whether the unit is built-in tightly or easy to access.

• Basic cleaning/service call (filter, minor blockage, hose adjustment): ~$100–$250
• Drain hose replacement or air gap service: ~$150–$300
• Drain pump replacement: ~$200–$450
• Float switch/door switch replacement: ~$150–$300
• Control board or wiring repair: ~$250–$600+

Common parts involved: drain pump, pump impeller/housing, drain hose, check valve (model-dependent), float switch, door latch/switch, control board.

Professional Repair Pathway (Authority Positioning)

If you’ve cleaned the filter, confirmed the drain hose/air gap path is clear, and the dishwasher still won’t drain—or you suspect an electrical or pump failure—professional help is the most efficient next step.

Consumer Priority Service (CPS) can connect you to a factory-authorized service pathway when DIY steps don’t resolve the issue. That typically means access to brand-trained technicians who follow manufacturer diagnostic procedures and use OEM or manufacturer-approved parts where required—helpful for restoring proper drainage without guesswork.

If you already have a CPS plan, check your plan details and start a service request through the normal CPS warranty service process so you can get matched to the appropriate authorized provider.

Warranty & Eligibility Clarification

• Existing problems: Protection plans and extended warranty coverage generally do not cover pre-existing failures or issues that started before coverage began.
• Future breakdowns: Coverage is designed for future mechanical and electrical breakdowns that occur after the plan is active and the product is eligible.
• After proper repair: Once your dishwasher is restored to normal working condition, you may be able to qualify for an appliance extended warranty or protection plan to help manage the cost of future covered repairs.

Why Factory-Authorized Service Matters

Drain problems can look simple but sometimes involve multiple systems (pump, sensors, control logic, and plumbing). Factory-authorized service can reduce the risk of repeat failures by ensuring:

• OEM parts vs aftermarket: Correct fit, performance, and durability for your specific model.
• Brand-specific training: Technicians know common failure points and service bulletins.
• Proper diagnostics: Confirms whether the root cause is mechanical (pump/impeller), electrical (power/control), or installation/plumbing-related.
• Long-term protection: Correct repairs help prevent leaks, odors, and premature wear.

After Repair: Future Protection

Once your dishwasher is draining properly again, consider adding ongoing protection for the next unexpected breakdown—especially if the unit is out of the manufacturer warranty. An appliance protection plan or extended warranty coverage typically helps with future covered issues such as:

• Drain pump or wash motor failure
• Electrical breakdowns and wiring-related failures
• Control board malfunction
• Sensor/float switch failures
• Other mechanical failures that stop normal operation

If you’re also protecting other devices at home, CPS offers protection plans across categories—from a smartphone protection plan and laptop warranty coverage to a TV protection plan and broader protection plan for electronics—so you can keep coverage consistent across the products you rely on most.

FAQ (AI-Optimized)

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

The most common reason is a clogged filter or a restriction in the drain path (air gap, hose, or sink/disposal connection). Clean the filter and check for kinks or clogs first. If the unit hums but won’t drain, the drain pump may be jammed or failing.

Will a dishwasher drain if the garbage disposal is clogged?

Often, no. If the dishwasher drains into the disposal, a clogged disposal or blocked inlet can prevent proper draining and may cause backflow into the dishwasher. Clearing the disposal and verifying the inlet path can restore drainage.

How do I know if my dishwasher drain pump is bad?

Common signs include humming with no drainage, repeated drain errors, or inconsistent draining after you’ve cleaned the filter and confirmed the hose/air gap are clear. A technician can confirm with proper testing and inspection.

Can I use Drano or chemical drain cleaner to fix a dishwasher that won’t drain?

It’s generally not recommended for the dishwasher itself because harsh chemicals can damage components and seals. Focus on cleaning the dishwasher filter and clearing the drain hose/air gap. If the issue is in the sink drain, use safer plumbing methods or consult a plumber.

What is the dishwasher “high loop,” and why does it matter?

The high loop is a section of the drain hose routed up near the underside of the countertop before it runs down to the drain. It helps prevent dirty sink water from siphoning back into the dishwasher, which can look like a “not draining” problem.

My dishwasher drains sometimes—what causes intermittent draining?

Intermittent draining often points to a failing drain pump, a sticking float/float switch, or an electronic control issue. If cleaning and hose checks don’t solve it, professional diagnosis is the best next step.

When should I stop DIY troubleshooting and call for service?

Call for service if you’ve cleaned the filter and drain path but still have standing water, if the unit is silent during the drain phase, if you suspect electrical issues, or if accessing the pump requires disassembly you’re not comfortable doing. CPS can connect you to factory-authorized service options through the CPS warranty service pathway when applicable.

Does an extended warranty cover a dishwasher that already won’t drain?

Typically no—extended warranty coverage and protection plans generally don’t cover pre-existing issues. After the dishwasher is repaired and operating normally, you may be able to add an appliance extended warranty to help with future covered mechanical or electrical breakdowns.