Why is there water standing in my dishwasher but it's not draining?

The most common reasons are a clogged filter, a blocked or kinked drain hose, or a jammed drain pump. Start by cleaning the filter and inspecting the hose for kinks or clogs. If those are clear, check the pump for obstructions. If you hear a humming sound, the pump may be stuck. If the issue persists after these checks, consult a professional.

Can a garbage disposal cause a dishwasher not to drain?

Yes. If your dishwasher drains into a garbage disposal, a clogged disposal or a missing knock-out plug in the disposal's inlet can block water from leaving the dishwasher. Run the disposal briefly to clear it, and check that the plastic plug inside the disposal's dishwasher inlet has been removed. Also, ensure the drain hose isn't kinked where it connects.

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

Signs of a bad drain pump include a humming noise when the cycle tries to drain, water that doesn't drain at all, or a pump impeller that won't spin manually. You can access the pump from the bottom of the dishwasher. If the impeller is free but the pump doesn't move water, or if the motor has no continuity when tested with a multimeter, the pump likely needs replacement.

Should I use a chemical drain cleaner in my dishwasher?

No. Chemical drain cleaners can damage dishwasher components like rubber seals and plastic parts, and they may void your warranty. Instead, use a physical method: remove the filter and clean it, clear the drain hose, and check the pump for debris. For minor clogs, running a cycle with a cup of white vinegar in a dishwasher-safe bowl on the top rack can help, but avoid mixing with other cleaners.

Why Your Dishwasher Won't Drain: 7 Common Causes Explained

Start Here: Quick Answers to Why Your Dishwasher Won't Drain

If your dishwasher won't drain, the cause is often one of a handful of routine issues. The most common are a clogged filter, a blocked or kinked drain hose, a faulty drain pump, a stuck check valve, or a problem with the garbage disposal connection. Each has a distinct set of signs, and most can be checked in under 15 minutes without special tools.

Before calling a repair technician, try the simplest step first: run a rinse cycle with a bowl of hot water on the bottom rack. This can dislodge a minor clog. If water still sits at the bottom after the cycle finishes, the issue is likely physical—something blocking the drain path—rather than an electronic failure.

This article walks through each common cause in order of likelihood, from the most easily fixed to the more involved. You'll learn what to look for, how to test each part, and when it's time to call a professional. Remember, if you're ever unsure about working with electrical or plumbing components, stop and consult a qualified appliance repair person.

Clogged Dishwasher Filter: The Number One Culprit

The filter at the bottom of your dishwasher traps food particles, grease, and debris. Over time, these accumulate and block the water from being pumped out. If your dishwasher won't drain and you notice standing water with visible food bits floating in it, a clogged filter is the most likely cause. Most modern dishwashers have a removable cylindrical filter that you can twist out and rinse under hot water.

To clean it, locate the filter at the bottom of the tub, usually under the lower spray arm. Twist it counterclockwise to release it, then rinse it under running water. Use a soft brush to remove stubborn residue. Replace the filter and run a short rinse cycle. This simple maintenance step resolves a surprising number of drainage failures.

If the filter is cracked, warped, or missing, order a replacement part from the manufacturer. Running the dishwasher without a filter allows large debris to enter the pump and drain hose, which can lead to more expensive repairs. Check the filter every month or two, especially if you scrape plates only lightly.

Blocked or Kinked Dishwasher Drain Hose

The drain hose carries wastewater from the dishwasher to your sink's drain line or garbage disposal. A kink in this hose—often caused by pushing the dishwasher too far back into the cabinet—restricts water flow and prevents draining. Similarly, a clog can form inside the hose from food buildup, grease, or a small object like a piece of glass or a berry stem.

To inspect the hose, first disconnect power at the circuit breaker. Slide the dishwasher out slightly to access the underside. Look for any sharp bends or pinches. If you see a kink, straighten it and secure the hose with a zip tie to keep it from recurring. For clogs, detach the hose from the sink drain and the dishwasher, then flush it with a garden hose or a long, flexible brush.

While the hose is off, check the connection point at the garbage disposal. A common issue is a missing knock-out plug—a small plastic piece inside the disposal's inlet that must be removed when installing a new dishwasher. If the plug is still in place, water has nowhere to go and backs up into the tub. Remove the plug with pliers, then reconnect the hose.

Faulty or Jammed Dishwasher Drain Pump

The drain pump is a small motorized impeller that pushes water out of the dishwasher. If it's jammed—often by a broken piece of glass, a toothpick, or a small bone—the pump won't turn, and water stays in the tub. You might hear a humming or buzzing sound when the cycle tries to drain, which indicates the motor is running but the impeller is stuck.

To check the pump, you'll need to access the bottom of the dishwasher. Unplug the unit and remove the lower kickplate. Locate the pump assembly, usually at the center rear. Look for any foreign objects caught in the impeller blades. Remove them with needle-nose pliers. Spin the impeller manually—it should rotate freely. If it's stiff or doesn't move, the pump may need replacement.

A more serious issue is a failed drain pump motor. If the pump spins freely but doesn't move water, or if it makes a loud grinding noise, the motor windings may be burned out. Testing this requires a multimeter to check for continuity. If you're not comfortable doing this, call a technician. Replacing a drain pump typically costs $150–$300, including parts and labor.

Stuck Check Valve or Clogged Air Gap

Many dishwashers have a check valve (also called a drain check valve or drain valve) located in the sump area. This small flap prevents dirty water from flowing back into the tub from the drain hose. If it gets stuck in the closed position—often due to a small piece of food—it blocks water from exiting. You can usually access it by removing the filter and looking for a small rubber flapper. Gently push it open with a spoon handle to dislodge debris.

Another component, the air gap, sits on your kitchen countertop near the sink—a small chrome cylinder with a plastic cap. Its job is to prevent backflow by introducing air into the drain line. If the air gap becomes clogged with food particles, it can cause a backup. Remove the cap, then use a toothbrush or a pipe cleaner to clear the inside. Run water through the gap to confirm it flows freely.

If neither the check valve nor the air gap is the issue, also inspect the sink's garbage disposal. Sometimes, a clogged disposal can cause dishwasher water to back up into the tub. Run the disposal for a few seconds to clear it, then check if the dishwasher drains. If not, the problem may be a more serious blockage in the branch drain line that connects to your home's plumbing.