Dishwasher Not Draining: Causes & Fixes (2026)

Dishwasher won't drain? The #1 cause is a clogged filter — here's how to check it, clear the drain hose, and test the drain pump before calling anyone.

Your dishwasher not draining? It finishes the cycle but the water just sits there. Before you call a repair tech (that’s $100+ just for them to look at it), run through these fixes in order — 8 out of 10 times it’s the first one.

The #1 cause: a clogged filter

Modern dishwashers trap food debris in a filter assembly at the bottom of the tub. When it fills up, water can’t get out.

Fix: pull the bottom rack, remove the filter (usually a twist-and-lift cylinder or a flat mesh panel), rinse it under the tap, and scrape off anything caked on. Also check the sump area underneath for broken glass, pits, or labels that slipped off jars. Replace the filter and run a rinse cycle.

Cause #2: a kinked or clogged drain hose

The drain hose runs from the dishwasher to the sink drain or garbage disposal. If it’s kinked, pinched, or sagging, water backs up.

Fix: pull the dishwasher out (it’s on adjustable feet — usually 2 screws holding it to the cabinet), find the hose, and check for kinks or a low spot where water pools. Disconnect it and flush it with a garden hose or by pouring water through. If it’s gunked up beyond cleaning, replace it — they’re cheap.

Cause #3: the air gap or disposal knockout

If your dishwasher drains into a garbage disposal, there’s a knockout plug in the disposal’s inlet that must be removed — many installers forget. There’s also a small cylinder on the countertop (the air gap) that can clog with debris.

Fix: check the disposal inlet for the knockout plug (tap it out with a screwdriver), and unscrew the air gap cap to clear any gunk.

Cause #4: the drain pump is failing

If the filter is clean, the hose is clear, and it still won’t drain — the drain pump (or its check valve) is the suspect. You’ll usually hear the pump hum but no water moving, or nothing at all.

Fix: test the pump with a multimeter for continuity. No continuity = replace the pump. Also check the check valve/flapper at the pump outlet — a stuck flapper is a common, cheap fix.

The 3-step process (works for any brand)

Clean the filter (cause #1 — do this first, always)
Check the hose + air gap (kinks, clogs, knockout plug)
Test the pump with a multimeter, then replace if dead

Parts & tools you’ll need

Dishwasher filter (if yours is cracked or warped)
Replacement drain hose (if kinked beyond repair)
Multimeter for testing the drain pump
Drain pump + check valve (if the pump tests dead)

FAQ

Q: Why is my dishwasher not draining but the filter is clean? A: Move to the drain hose — check for kinks and flush it. Then check the disposal knockout plug and air gap before suspecting the pump.

Q: Can a clogged garbage disposal cause the dishwasher not to drain? A: Yes — if the disposal is clogged, water backs up into the dishwasher through the shared drain. Run the disposal with water flowing; if that fixes it, that was it.

Q: How much does it cost to fix a dishwasher that won’t drain? A: DIY: $0–$60 (filter, hose, or pump). Hiring a tech: $150–$350 depending on the part.

Codes and part locations vary by model — check your manual before ordering parts. When in doubt, a licensed appliance tech is worth the call.