Dishwasher Won't Drain — WDT790SLYM3 (What Part Fixes This Problem?)
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Understanding the Problem
If your Whirlpool WDT790SLYM3 is finishing a cycle but standing water remains in the tub, or you hear the pump struggle and still water doesn't go out, the unit is not draining properly. This is a common issue caused by either a blockage in the drain path (filter, sump, drain hose, or garbage disposal), a failed drain pump or check valve, or an electrical/control problem preventing the pump from running. Start with the easy checks: remove food debris from the filter and sump, inspect and run water through the drain hose, and verify the knockout plug was removed from the garbage disposal if newly installed. If those are clear, the most likely parts to inspect are the drain pump/sump assembly and the one-way check valve. You can also put the dishwasher into a diagnostic/drain cycle and listen — a healthy pump will run audibly and move water; a failed pump may hum, be silent, or run without moving water due to internal damage or blockage.
Common Symptoms
Water remains in the dishwasher after a cycle, gurgling or humming noises during drain, error codes related to drain (if displayed), unpleasant odors from standing water, or repeated drain cycles without success.
Common Causes
- Clogged filter, sump or drain hose (food debris, broken glass, grease buildup)
- Failed drain pump or impeller assembly (electrical or mechanical failure)
- Blocked or stuck check valve / garbage disposal knockout plug not removed
Popular Parts That Fix This Problem
These are the most common replacement parts that fix this problem. When you're ready to order, click below to find the right part at PartsDiscount.com — just search by your appliance model number for a guaranteed fit.
Helpful Repair Tip
Run the dishwasher’s drain cycle and listen at the lower front (kick) panel. If you hear the pump motor run but no water moves, the pump or internal impeller is likely bad. If it’s silent and no pump sound, check for power to the pump with a multimeter before replacing it.
Frequently Asked Questions
How much will it cost to fix a dishwasher that won't drain?
If the problem is a clogged filter or hose, the repair can be free (DIY cleaning) or under $50 if you buy a replacement hose or filters. Replacing the drain pump/sump typically costs between $60 and $200 for the part, plus labor if you hire a technician. If the control board is at fault, parts and labor can raise the cost significantly; always diagnose pump power first.
Can I replace the drain pump myself and how do I test it?
Yes, a homeowner with basic tools can replace the drain pump. Safety first: disconnect power and water. Remove the lower kick panel, siphon standing water, disconnect the drain hose and electrical connector, and unbolt the pump/sump. To test before replacing, put the dishwasher into a drain cycle and use a multimeter to check for voltage at the pump connector when the drain should be active (typically ~120 VAC). If voltage is present and the pump doesn't run, replace the pump. If no voltage, trace wiring back to the control board/relay or door latch switch.
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Whether your dishwasher won't drain, your dryer stopped heating, or your fridge isn't cold, we've created simple repair guides for the most common appliance problems homeowners face. Each guide explains what's going wrong, the most likely causes, and which replacement parts fix the issue. When you're ready to order, we link directly to PartsDiscount.com where you can search by model number and get the right part shipped fast.