How to Fix a Dishwasher That Won’t Drain

Opening the dishwasher to a puddle of gray water pooled around the drain is one of the most common complaints homeowners have, and the good news is that it’s usually one of the cheapest problems to fix yourself. Before you call a repair tech, run through the checks below — in most cases the culprit is a clogged filter, a kinked drain hose, or a garbage disposal knockout plug that was never removed.

Dishwasher Won’t Drain: Quick Overview

A dishwasher won’t drain for one of a handful of predictable reasons: a clogged filter or sump basket, a blocked or kinked drain hose, a faulty drain valve or check valve, or a garbage disposal that’s either clogged itself or still has its inlet knockout plug in place from installation. If your kitchen sink is also draining slowly, start with our guide to clearing a clogged kitchen sink, since a shared drain line can back up into the dishwasher. And if the disposal hums but won’t turn at all, see our garbage disposal won’t turn on guide first, since most dishwashers drain through the disposal.

What’s Actually Wrong

Food particles, grease, and broken glass settle in the filter basket at the bottom of the tub over time. Once that filter clogs enough, water can’t get pulled into the pump fast enough to drain properly, and you’re left with standing water after every cycle. The second most common cause is the drain hose — the corrugated tube running from the dishwasher to either the garbage disposal or the sink’s drain tailpiece. It can kink behind the cabinet, or it can clog with the same grease and food debris. Less often, the drain valve or check valve inside the pump assembly fails and lets water flow the wrong way, or a new dishwasher was installed without removing the garbage disposal’s inlet knockout plug, which blocks the connection entirely.

Tools You’ll Need

• Towels and a shallow bowl or cup for bailing out standing water
• Needle-nose pliers
• Flexible drain/bottle brush
• Screwdriver (Phillips and flathead)
• Bucket or basin to catch water from the drain hose
• Flashlight

Step-by-Step Fix

1. Bail out the standing water. Use a cup and towels to remove as much water from the tub as you can before you start working.
2. Pull and clean the filter. Most modern dishwashers have a twist-out filter assembly at the bottom of the tub, under the lower spray arm. Twist it a quarter turn, lift it out, and rinse it thoroughly under the sink, using a flexible brush to clear the mesh screen.
3. Check the sump/drain area. With the filter out, shine a flashlight into the sump basket and remove any visible debris, glass shards, or food chunks by hand.
4. Inspect the drain hose. Turn off power at the breaker, then pull the dishwasher out from under the counter (most slide out after removing the two mounting screws under the countertop lip). Check the corrugated drain hose for kinks and straighten any you find.
5. Clear the hose and disposal connection. Disconnect the drain hose at the disposal or sink tailpiece end (have a bucket ready) and check for a clog. If your dishwasher connects to a garbage disposal, make sure the plastic knockout plug inside the disposal’s inlet was removed — this is a common miss on new disposal installs and completely blocks drainage.
6. Reconnect and run a test cycle. Reattach the hose, restore power, and run a short cycle, watching the connections for leaks and confirming the tub drains fully at the end.

Watch the Repair

Drain problems look the same across brands. This walkthrough covers the filter, the drain hose and the check valve on Whirlpool, GE, LG and Maytag machines, in the same order as the steps above.

When to Call a Pro

If you’ve cleaned the filter, cleared the hose, and confirmed the disposal isn’t the problem but the dishwasher still won’t drain, the drain pump or drain solenoid/valve itself may have failed, which typically requires disassembling the base of the unit. That’s a reasonable point to call an appliance repair technician, especially on a dishwasher under five years old where a part replacement is more cost-effective than buying new. Use our repair or replace decision tool to help weigh the cost of a repair against replacing an older unit.