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True Trade Path

Diagnostic guide

Dishwasher Not Draining

Standing water in the bottom of your dishwasher after a cycle — most causes are local and fixable without a service call.

System
Plumbing
Causes covered
7
You can check
5 without a technician

Stop and read this first

  • Disconnect power at the breaker before reaching into the dishwasher.
  • Standing water in the dishwasher can harbor bacteria — run a sanitize cycle after clearing the drain.
  • If the dishwasher shares a drain with a garbage disposal, never run the disposal while the dishwasher is draining.

Work through these in order

Ordered from most to least likely. Working top down means you rule out the cheap, common causes before paying anyone to look at the expensive, rare ones.

  1. Clogged filter or drain basket

    CommonYou can check
    How to check
    Water pools at the bottom after every cycle. Filter at the bottom of the tub is coated with food debris.
    The fix
    Remove and clean the filter assembly. Rinse under running water and reinstall. Clean monthly.

  2. Blocked drain hose

    CommonYou can check
    How to check
    Hose running from the dishwasher to the disposal or drain is kinked, clogged, or installed with a high loop missing.
    The fix
    Disconnect the hose and flush with water. Ensure the hose has a high loop at least 20 inches above the floor.

  3. Garbage disposal knockout plug not removed

    CommonYou can check
    How to check
    New dishwasher or new disposal installation. Dishwasher drains through the disposal.
    The fix
    Knock out the plastic plug inside the disposal inlet where the dishwasher hose connects. This is the most common new-install mistake.

  4. Clogged air gap (if installed)

    CommonYou can check
    How to check
    Water spills from a small cylinder mounted on the sink or countertop during drain cycle.
    The fix
    Remove the air gap cap and clean debris from the inner tube. Flush with water.

  5. Failed drain pump

    PossibleNeeds a pro
    How to check
    Filter and hose are clear but water remains. You hear the pump attempt to run but nothing drains.
    The fix
    A technician replaces the drain pump ($150 to $350). Check for debris jamming the pump impeller first.

  6. Main line or sink drain clog

    PossibleYou can check
    How to check
    Kitchen sink also drains slowly. Multiple fixtures gurgle when the dishwasher runs.
    The fix
    Snake the sink drain ($100 to $250 DIY or professional). If multiple fixtures are affected, the main line may be blocked ($200 to $800).

  7. Check valve stuck closed

    UncommonNeeds a pro
    How to check
    Water drained previously but stopped after a long period of disuse.
    The fix
    A technician replaces the check valve in the drain hose or pump assembly ($100 to $250).

How to find a good plumber

Before you sign a contract for this job, use our guide on how to find a good plumber: verify the licence at the state board, compare three itemized quotes on the same scope, and put permit responsibility and change-order rules in writing.

Read the plumber hire guideCheck if your quote is fairVerify licences by state

For trade owners

Pricing this job as a contractor?

Homeowners see national ranges on this page. If you are building the estimate, use the same scope assumptions — then price to burdened labor, overhead recovery and a real margin.

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Find a licensed pro

When you are ready to hire for dishwasher not draining, start with licence verification — not with whoever answered first.

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Rankings are never sold. Order reflects verification depth and relevance, not payment.
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Verify any licence yourself before signing: state licensing hub.

Common questions

Could clogged filter or drain basket be causing this?
Water pools at the bottom after every cycle. Filter at the bottom of the tub is coated with food debris. Remove and clean the filter assembly. Rinse under running water and reinstall. Clean monthly.
Could blocked drain hose be causing this?
Hose running from the dishwasher to the disposal or drain is kinked, clogged, or installed with a high loop missing. Disconnect the hose and flush with water. Ensure the hose has a high loop at least 20 inches above the floor.
Could garbage disposal knockout plug not removed be causing this?
New dishwasher or new disposal installation. Dishwasher drains through the disposal. Knock out the plastic plug inside the disposal inlet where the dishwasher hose connects. This is the most common new-install mistake.
Could clogged air gap (if installed) be causing this?
Water spills from a small cylinder mounted on the sink or countertop during drain cycle. Remove the air gap cap and clean debris from the inner tube. Flush with water.

Once you know what it is

Step one

Know what it should cost

Get the range before you call, so the first number you hear is not the only number you have.

Step two

Decide repair or replace

On equipment near end of life, the repair is usually the first of several.

Step three

Check the quote

Compare against the typical range and confirm the terms before you sign.

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What the fix costs

Tools for this decision

Other symptoms