How to Fix a Dishwasher That Won't Drain

A dishwasher that won't drain is usually caused by a clogged filter, blocked disposal connection, or kinked drain hose. Start with the filter and work your way through the drainage system.

1. Start at the Source. Remove the bottom dish rack and locate the cylindrical filter at the bottom of the tub. Unscrew it counterclockwise and lift it out. Rinse under hot water and scrub away food debris with an old toothbrush. If heavily clogged, soak in warm soapy water for 15 minutes before cleaning.
2. Unblock the Exit Path. If your dishwasher drains through a garbage disposal, run the disposal with cold water for 30 seconds to clear any blockages. Many drainage issues stem from a backed-up disposal that prevents dishwasher water from flowing out.
3. Fix Kinks and Loose Clamps. Look under your kitchen sink for the dishwasher drain hose. Check where it connects to the garbage disposal or sink drain pipe. The connection should be tight and the hose shouldn't have any visible kinks or clogs. If loose, tighten the clamp with pliers.
4. Unclog Every Jet. Remove the bottom spray arm by lifting or unscrewing it. Hold it up to the light and look through the holes for clogs. Use a toothpick or thin wire to poke out debris from the holes. Rinse thoroughly and reinstall. Repeat for the upper spray arm if accessible.
5. Clear the Air Gap. If you have an air gap on your countertop near the sink, remove its chrome cap and plastic cap underneath. Clean out any debris inside with your fingers or a small brush. This prevents backflow and can cause drainage problems when clogged.
6. Flush and Dissolve Buildup. After reassembling everything, run an empty dishwasher cycle with 2 cups of white vinegar placed in a dishwasher-safe bowl on the top rack. This helps break down grease and soap buildup in the system. Follow with a cycle using dishwasher cleaner or baking soda.
7. Listen for Pump Failure. If water still won't drain, the drain pump may be failing. Listen during the drain cycle for unusual grinding or humming sounds. A working pump makes a steady humming noise. If the pump is silent or making grinding sounds, it likely needs professional replacement.