At a glance
Symptoms
- • Standing water at the bottom of the tub after the cycle ends
- • Dirty water with food debris pooling around the filter
- • Dishwasher mid-cycle stops with water remaining
- • Gurgling or humming sound from the drain pump but no water moving
- • Error code (E24, E25, LE, OE depending on brand) for drain fault
Common causes
- • Garbage disposal drain connection clogged or knockout plug never removed (most common on new installs)
- • Drain filter at the bottom of the tub clogged with food, glass, labels, or grease
- • Drain hose kinked behind the dishwasher or clogged with sludge
- • Drain pump impeller jammed by glass shards, fruit pits, or a toothpick
- • Faulty drain pump motor (no hum, no flow)
- • Stuck check valve in the drain pump preventing water from leaving
- • Control board not sending the drain signal (rare, but seen on Samsung NX/DW80 series)
Safety First — Read Before You Start
- •Turn off power at the circuit breaker before reaching into the pump area — even an unplugged dishwasher may have residual power on hardwired models.
- •Shut off the water supply valve under the sink before disconnecting any hoses.
- •Wear cut-resistant gloves when removing the filter or reaching into the sump — broken glass is the single most common cause of jammed impellers and can slice your fingers.
- •Never run the dishwasher with the kick-plate removed and water visible — splashing on the live pump motor can cause shock.
- •Do not use chemical drain cleaners (Drano, Liquid-Plumr) inside a dishwasher — they damage rubber seals and the stainless tub.
Tools & supplies you'll need
- Phillips and flat-head screwdrivers
- Channel-lock pliers or adjustable wrench
- Wet/dry shop vac or large sponge and towels
- Flashlight
- Multimeter (for testing pump motor continuity)
- Coat hanger or zip tie (to fish debris from the drain port)
- Bucket or shallow pan to catch hose water
Step-by-step instructions
Bail out standing water and clear the filter
Start by removing the pooled water using a shop vacuum or by soaking it up with towels and a bucket. Once the basin is clear, remove the cylindrical filter at the base. Brands like Bosch, KitchenAid, and Whirlpool typically use a quarter-turn mechanism; simply rotate and lift. Clean the mesh under warm running water. Don't forget to lift the flat fine-mesh screen beneath it. Use your flashlight to scan the sump area for stuck debris like plastic bits, lemon seeds, or broken glass shards.
Tip: A dirty filter is the main reason for poor drainage. While manufacturers suggest monthly maintenance, many homeowners overlook this. If your filter is coated in grime, this is likely your point of failure.
⚠ Warning: Always use gloves when feeling around the sump area; glass shards are frequently hidden there, even if you cannot see them.
Check the garbage disposal connection
If your dishwasher is new or was recently installed, the issue is often the disposal knockout plug. Inspect the point where the drain hose meets the disposal under your sink. If the plug was never removed during the initial setup, water cannot exit. If you see a solid plastic disc inside the disposal inlet, use a screwdriver and hammer to carefully knock it out, then retrieve the plastic piece before reattaching the hose.
Tip: If you have a disposal, run it for about 15 seconds before starting your dishwasher. This clears out any leftover food sludge that might otherwise back up into the drain hose.
⚠ Warning: Never put your hand inside the disposal, even if it is disconnected from power. Use pliers to extract any debris.
Inspect the drain hose for kinks and clogs
You may need to remove two mounting screws under your countertop to slide the unit out slightly. Follow the corrugated drain hose from the dishwasher to the high loop under the sink, checking for sharp bends or pinches against the wall. If you find a kink, straighten it out. If the hose looks clear, disconnect both ends, hold it over a bucket, and use a coat hanger or a flush of water to clear out any hardened grease buildup common in older homes.
Tip: To prevent back-siphoning from the sink, ensure your drain hose features a high loop at least 32 inches above the floor, or connects to an air gap on the counter. This is standard practice throughout the Pacific Northwest to keep sink water out of your appliance.
⚠ Warning: Ensure the power is off before moving the unit to avoid pulling on live wiring.
Clear the drain pump impeller
If the previous steps didn't help, the pump impeller might be blocked. With the dishwasher pulled out and the power off, lay the unit on its back—placing a towel under the door first. Locate the drain pump on the bottom of the tub, usually on the left. On many units, you can remove the pump cover from inside the tub to access the impeller. Spin it with your finger; it should move without resistance. If you find obstructions like toothpicks or glass, remove them to restore function.
Tip: For Bosch SHE/SHX series owners, the drain pump is easily accessible; just pop off the white plastic cover inside the sump with a flat-head screwdriver.
⚠ Warning: Wear cut-resistant gloves. Glass fragments from broken dishware are the most frequent cause of impeller jams.
Test the drain pump motor electrically
If the impeller is clear but the pump remains silent, test the motor using a multimeter. Disconnect the pump wires and check the resistance across the terminals. A functional motor typically shows between 50 and 300 ohms, though you should verify this against your specific service manual. An 'OL' (open loop) reading indicates a dead motor. Replacing the pump is a common repair, though it requires some technical comfort.
Tip: Always consult your specific appliance manual for the exact resistance values for your model.
⚠ Warning: Never apply voltage to a pump that is still mounted in the sump while water is present.
Verify the check valve and run a test cycle
Check the small flapper or check valve at the discharge port; it should swing freely to prevent water from flowing back into the tub. If it is stuck, clean it or ensure it is seated correctly. Once reassembled, restore power and water, then run a short 'Rinse Only' cycle to confirm the unit drains properly. Check for leaks around the hose clamps.
Tip: Running a hot cycle with a cup of white vinegar in the upper rack can help dissolve residual grease in the pump and hose after the repair.
⚠ Warning: Double-check all hose clamps for tightness to prevent leaks under the sink.
If still failing — diagnose the control board signal
If the pump is functional but fails to activate, the control board may not be sending the signal. This is seen occasionally in Samsung DW80 or certain Bosch 800 series models. Use a multimeter to see if 120V reaches the pump during the drain cycle. If there is no voltage, the board is likely faulty. Control board replacement is best handled by a professional unless you are experienced with electronics.
Tip: Check for loose wire connections at the control board before assuming the board itself has failed.
⚠ Warning: Working with control boards involves sensitive electronics; ensure you are grounded and the power is off.
Brand-specific notes
Some brands have known design quirks worth knowing about before you start.
Bosch
Bosch SHE, SHX, and SHP series (300/500/800) collect a surprising amount of sediment in the lower sump and pump cover even though they have a self-cleaning filter design. Pop off the white plastic pump cover at the bottom of the tub once a year — you will almost always find food sludge underneath. The drain pump itself (part 00611332 and similar) is one of the most reliable in the industry; if it has truly failed, the unit is probably 10+ years old.
KitchenAid
KitchenAid KDTM, KDTE, and KDPE series share the Whirlpool platform. The drain hose on these is notoriously skinny and clogs with grease around year 5-7. If clearing the filter does not solve it, blow compressed air through the disconnected drain hose — you will often dislodge a plug of solidified grease. Replacement hose is ~$25.
Whirlpool
Whirlpool WDT, WDF, and WDTA series often throw an "F8 E1" or "F9 E1" error for drain faults. The chopper blade in the sump (a small spinning blade that grinds food before it leaves) gets bound up by labels from canned goods and orange peels. Lift the chopper cover and clear the blade — this is a 2-minute fix that resolves most "drain pump won't spin" errors on these models.
Samsung
Samsung DW80 and DW60 series have well-documented control board failures that present as drain faults — the pump is fine but never gets a signal. Look for an "OE," "5E," or "LE" code. If the pump hums normally during the wash phase but goes silent at drain time, the board is the suspect. Samsung extended warranty on some models covers this; check your serial number on Samsung's site before paying out of pocket.
LG
LG LDF and LDP series use a direct-drive drain pump that is quiet but glass-sensitive. A single shard from a broken wine glass will jam the impeller. The pump on LG models is accessed from the bottom (tip the unit back) rather than from inside the tub — keep towels handy because residual water always drips.
What our techs see most often
When A-Fix receives a no-drain call, we perform a quick phone triage. We ask if a disposal was recently installed or if the filter has been cleaned. Frequently, the issue is simply a forgotten disposal knockout plug from a recent kitchen remodel. Checking this yourself can save you the cost of a professional service visit.
When to call a professional
- → You have cleared the filter, hose, and disposal connection but standing water remains
- → The drain pump motor is humming but not moving water and the impeller is not jammed
- → Error code points to the control board (E24/E25 on Bosch, OE on Samsung, F9 on Whirlpool with no chopper jam)
- → Water leaks from the bottom of the dishwasher whenever it tries to drain — likely a cracked sump or split hose internal to the unit
- → The unit is hardwired and you are not comfortable working in the breaker panel
- → You smell burnt plastic from the pump area (motor windings burned out — replace, do not run again)
Dishwasher Maintenance & Replacement Tasks
Step-by-step guides for individual maintenance jobs related to this appliance.
How to Clean a Dishwasher Filter (All Brands)
How to Clean Dishwasher Spray Arms (Unclog the Jets)
How to Descale a Dishwasher with Vinegar or Citric Acid
How to Replace a Dishwasher Door Gasket
Frequently asked questions
Why is there standing water in my dishwasher after every cycle?
A small amount (under a cup) at the bottom of the sump is normal on Bosch and other European-style dishwashers — it keeps the pump seal from drying out. But more than that, especially dirty water reaching the heating element, indicates a drain blockage. Start with the filter and the garbage disposal connection.
Can I use vinegar or baking soda to unclog my dishwasher drain?
Vinegar and baking soda will not clear a physical blockage like a glass shard or a knockout plug. They can break down minor grease buildup in the drain hose if poured in and left to sit. Run a cup of white vinegar in the upper rack on a hot empty cycle once a month as preventive maintenance.
How much does it cost to fix a dishwasher that won't drain?
A clogged filter or disposal knockout is free — just your time. A new drain hose runs $25-40 in parts. A replacement drain pump is $150-280 installed. If the control board has failed, expect $280-450. At A-Fix we charge a $90 diagnostic fee that is credited toward the repair.
Should I run the garbage disposal before starting the dishwasher?
Yes. The dishwasher drains into the disposal chamber on most installations. If the disposal is full of food scraps, the dishwasher water has nowhere to go and backs up into the tub. A 15-second run before each cycle clears the path.
My dishwasher is brand new and has never drained right — what do I do?
Almost certainly the installer forgot to remove the garbage disposal knockout plug. This is so common it is the first thing we check. Look under the sink, disconnect the dishwasher drain hose from the disposal, shine a light into the disposal inlet — if you see a solid white plastic disc, that is your problem. Knock it out with a flat screwdriver.
Related Repair Guides
Why Your Dishwasher Isn't Cleaning: A PNW Repair Guide
If your plates are coming out with a gritty texture, filmy residue, or food flecks, the culprit is rarely the soap. In the Pacific Northwest, high mineral levels in our water supply frequently lead to scale buildup, clogged spray arm ports, and restricted water flow. These issues account for the vast majority of cleaning complaints. Most of these repairs are straightforward and can be completed in 30 to 90 minutes without needing specialized components.
Dishwasher Leaking Water on the Floor: Causes and Fixes
Finding water pooling in front of your dishwasher is a stressful situation that demands quick attention, as every subsequent cycle can lead to worsening water damage in your home. Fortunately, the culprit is usually limited to five specific areas: the door gasket, improper door closure, the water inlet valve, hose connections, or the float assembly. You can typically identify the source in about 30 minutes, and most repairs are quite affordable, often requiring less than $50 in parts.
How to Clean a Dishwasher Filter (All Brands)
A blocked filter is the primary culprit behind filmy dishes and unpleasant smells. Follow this guide to remove and scrub your filter assembly to maintain optimal cleaning power and protect your drain pump.