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Why is my dishwasher not draining?
If your dishwasher finishes a cycle but leaves standing water at the bottom, something is blocking or preventing drainage. This is one of the most common dishwasher complaints we hear from homeowners in Ontario, Riverside, and across the Inland Empire.
The good news: dishwasher drainage problems are usually fixable in a single visit, and the cause is almost always one of the following five things.
5 most common reasons a dishwasher won't drain
1. Blocked drain filter (most common) — the filter at the bottom of your dishwasher tub catches food debris. When it gets clogged, water can't flow through to the drain pump. This is the first thing to check — and the easiest to fix yourself.
2. Failed drain pump — the pump forces water out of the tub through the drain hose. When the pump motor fails or the impeller gets jammed by debris, drainage stops completely. You may hear a humming sound as the pump tries but fails to move water.
3. Kinked or clogged drain hose — the hose that carries water from the dishwasher to your sink drain can kink behind the machine or get blocked by accumulated grease and food particles over time.
4. Garbage disposal connection blocked — if your dishwasher drains into a garbage disposal, a clogged disposal or a still-intact knockout plug (on a new disposal) will prevent drainage entirely.
5. Air gap or high loop missing or blocked — dishwashers need either an air gap device or a drain hose high loop to prevent backflow. If this is missing or blocked, water siphons back into the tub after draining.
What can you check yourself?
- Remove the bottom rack and twist out the drain filter. Rinse it under hot water and scrub with a soft brush. Reinstall and run a short cycle.
- If the dishwasher drains into a garbage disposal, run the disposal fully before starting the dishwasher.
- Check behind the machine for a kinked drain hose.
- If E24 or a drain error code appears, see our guide on Bosch dishwasher E24 error codes for brand-specific steps.
If water is still standing after these checks, the drain pump has likely failed and needs to be replaced by a technician.
Real repair case: dishwasher not draining in Ontario, CA
A homeowner in Ontario contacted us after their dishwasher stopped draining completely. Even after running the cycle twice, dirty water pooled at the bottom of the tub. The filter was clean — they had already checked it.
Our technician arrived the same day. After testing the drain pump directly, he confirmed the pump motor had failed — it was drawing power but not turning. No amount of filter cleaning would fix a failed pump motor.
He replaced the drain pump with a direct replacement part, cleaned the drain line to remove any residual buildup, and ran a complete test cycle. The dishwasher drained perfectly on the first run.
The entire service call took under 90 minutes.
How much does dishwasher drain pump replacement cost?
A drain pump replacement typically costs $150–$280 depending on the brand and model. For most dishwashers under 10 years old, repair is almost always the smarter choice compared to the cost of a new machine. If you're unsure, our technician will give you an honest assessment before starting any work.
Dishwasher not cleaning even after draining?
Sometimes a partially blocked drain creates a cascade of problems — dishes come out dirty, there's standing water, and the machine smells. If your dishwasher drains but still doesn't clean properly, read our full guide on why dishwashers don't clean dishes. We also fix dishwashers leaking from the bottom, which is sometimes related to a drainage backup.
Same-day dishwasher repair in Ontario and nearby cities
We provide professional dishwasher repair across Ontario, Riverside, Eastvale, Corona, Chino, and Chino Hills. If your dishwasher has standing water after a cycle, call us today — most drain pump repairs are completed in one visit.
