Section 4 · Appliances
Dishwasher Problems and Repair Guides
A dishwasher fills, sprays, then pumps its water through a filter, a drain hose and the sink plumbing. Most drain problems start at the filter, the garbage disposal, the hose loop or the air gap. Start with the problem table, then clean the filter on a schedule.
Start with the symptom
Filter DIY
Water leaves the tub through a removable filter at the bottom. It keeps food, labels and glass away from the pump. On Frigidaire models a cylinder filter catches broken glass, bones and pits above a flat coarse filter.[3][2][8] Clean the filter: Filter
Sump DIY
The recessed well around the filter, right above the pump. Whirlpool reads the water level here: water just above the filter means a partial blockage. Pick out debris with gloves on and the breaker off.[3] Clear the sump: Sump
Drain pump Pro only
The pump pushes the water out at the end of each wash and rinse. A steady hum with no water moving points to a jammed impeller, grinding to hard debris, and silence to an electrical or control fault.[3] What the sounds mean: Drain pump
Drain hose DIY
The hose runs from the pump into the sink cabinet. It must not be kinked, crushed or trapped under the dishwasher. Frigidaire asks for at least 32 inches of height above the floor before it drops to the drain.[3][6][9] Check the hose: Drain hose
Air gap DIY
A small fitting on the counter, under a cap you can pull off. It stops sink water from flowing back into the tub. Water spilling out of it during a drain means the clog is further down, in the hose or the sink plumbing.[3][8] Clean the air gap: Air gap
Garbage disposal inlet DIY
Many dishwashers drain into a side inlet on the disposal. A new disposal comes with a knockout plug in that inlet, and if it stays in, nothing drains. A disposal full of food blocks the water too.[3][5][6] Check the disposal: Garbage disposal inlet
Sink tailpiece and trap Plumber if the sink is slow too
Last comes the house drain. Run the faucet for 30 seconds: if the sink does not drain either, the clog is in the home’s plumbing, and Samsung says to call a plumber.[6][3] Run the sink test: Sink tailpiece and trap
- No air gap? Then a high loop. Without an air gap, the hose has to rise in a high loop fastened to the underside of the counter before it drops to the drain. Without one or the other, dirty water can flow back into the tub. Local codes decide which one you need.[3][6]
How a dishwasher moves water
A dishwasher works in rounds of fill, spray and drain. Frigidaire's manual describes a cycle that drains for a few seconds first, then fills enough to cover the filter area. Water is pumped through the spray arms, and soil passes through the filter and down the drain as the water is pumped out. The number of fills depends on the cycle.[1]
The drain path has four parts. The filter in the tub bottom keeps food away from the pump; Bosch says it stops particles from clogging the pump and landing back on your dishes.[2] The drain pump pushes the water out at the end of each wash and rinse. The drain hose carries it under the sink to the sink drain, an air gap or a garbage disposal.[3] Whirlpool says a high loop in the hose, or a working air gap, stops dirty water from flowing back into the tub.[3]
A block at any of those points leaves water in the tub. Frigidaire says a little water in the bottom after a cycle is normal; water covering the filter screen is not.[4]
Dishwasher safety basics
The heating element in the tub bottom stays hot after a cycle, so let it cool before you clean inside.[1] Feel slowly around the sump, which can hold broken glass.[3] Don't pour drain cleaner into the tub; Whirlpool says drain-opening chemicals can damage the dishwasher.[3] Call a technician if you smell burning, see damaged wiring, or the breaker trips again and again.[3]
Common dishwasher problems and the first check
Each first check is safe for an owner and needs no tools.
| Symptom | First check | Guide |
|---|---|---|
| Water covers the filter after a cycle | Remove the filter and wash it under running water with mild soap and a soft brush.[2] | dishwasher drain fixes |
| Frigidaire shows i20 or i40 | Empty the glass trap in the middle of the filter.[1] | — |
| Bosch shows E24 | Check the drain hose and the filter, then the disposal plug.[5] | — |
| Stopped draining after a new disposal | Make sure the disposal's knockout plug was removed.[3] | check the garbage disposal |
| Sink is slow too | Run water in the sink for about 30 seconds; if it won't drain, call a plumber.[6] | — |
| Pump hums but water stays | Look for glass or bone in the sump with the power off.[3] | — |
For washers, dryers and other machines, see all appliance repair guides.
Dishwasher upkeep and expected life
Clean the filter. Bosch says to clean it regularly, and Whirlpool says more often if you cook and run the dishwasher a lot.[2][3] On Frigidaire models with a glass trap, empty the trap when debris collects in it.[1]
Scrape plates before you load them, and run hot water at the sink before you start a cycle, as Whirlpool suggests.[3] If the dishwasher drains into a disposal, Frigidaire's manual says to make sure the disposal is completely empty before you run the dishwasher.[1]
Check the drain hose after any under-sink work, and clean out the air gap cap now and then.[3] Samsung says the hose must not be kinked and must follow local rules for an air gap or a high loop.[6]
Expect a shorter life than other big appliances. A 2007 NAHB study put dishwashers at about 9 years, among the shortest of the major appliances.[7] Weigh a big repair on an older machine with the repair-or-replace calculator.
Sources
“Dishwasher Use & Care Manual (A17894301C, November 2025)” · PDF · pp. 3, 5, 13 · accessed
“Samsung dishwasher is not draining” · accessed
“Study of Life Expectancy of Home Components” · PDF · Appliances findings and Table 1 (Dishwashers) · accessed
“Dishwasher Glass Trap and Filter Guide” · accessed
“Dishwasher - Drain Hose Guide” · accessed
How this page was made
This page was drafted with AI assistance from the manufacturer and safety sources listed above, then checked against those sources in an AI-assisted review. No licensed technician reviewed it. Last reviewed . Our methodology