Bottom-rack failure often follows a blocked lower arm, filter debris, cookware blocking rotation or weak circulation. With the machine off, spin the arm by hand and look under it for a label, seed, piece of glass or a utensil handle.
What this covers
- Dishwashers · spray system
What it does not cover
Differential
Likely causes of “Dishwasher bottom rack is not getting clean”, and how to tell them apart
- 1
Something is under or in the lower spray arm
What separates it The arm sticks or spins in fits, and the dishes above its dead spot come out dirty.
How to confirm With the machine off, spin the arm by hand and look under it for a label, seed, piece of glass or a utensil handle.
- 2
Filter debris is restricting circulation
What separates it Gritty residue on dishes, slow drain, and a filter with visible food.
How to confirm Remove and rinse the filter as the manual describes, and look at the sump below it.
- 3
Cookware is blocking the arm or the spray path
What separates it Only the bowls or pans in the same spot are dirty and the arm cannot complete a full turn.
How to confirm Load a normal set, close the door, and check for contact by turning the arm by hand.
- 4
Weak circulation from the pump
What separates it Both racks have poor spray and there is a humming or straining sound.
How to confirm Run an empty cycle and listen for spray on the tub walls; leave a weak pump to service.
Before you touch a setting
Record this first — changing settings destroys the evidence
- Which dishes come out dirty and where they sit relative to the lower arm.
- Whether the arm turns freely by hand with the door open.
- Whether the filter and sump were cleaned recently.
Try in this order
0 of 4 completedObserve before changing anything
ReversibleRotate the lower arm by hand and check for labels, seeds, glass or utensils beneath it.
Isolate the failing boundary
ReversibleClean the filter and approved spray holes and run an empty circulation test.
Apply the narrow correction
ReversibleReload cookware so the arm clears and face dirty surfaces toward the spray.
Verify the result and stop at the boundary
ReversibleStop for broken spray parts, grinding pump noise or no wash circulation.
Stop boundary
When this stops being a self-service repair
- !Stop for broken spray parts, grinding pump noise, or no wash circulation in an empty test cycle.
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Should the bottom rack be the cleanest?+
It usually gets the strongest spray, so uneven results in the lower rack alone point at the lower arm, the filter or how the rack was loaded.
Why does the bottom rack stay dirty?+
A tall item blocking the lower spray arm, debris in the filter and sump, or an arm that has come off its mount. Check that the arm spins freely and the filter is clean.
Does pre-rinsing help?+
Scraping is enough. Heavy pre-rinsing can make the sensor think the load is clean and shorten the wash.
Why is the bottom rack worst?+
The lower spray arm serves it, and it may be blocked or unable to spin freely.
What should I check first?+
Spin the arm by hand, check its nozzles and clean the filter.
Does loading matter?+
Yes. Large items can block the arm and shield other dishes.
Why is the bottom rack worse than the top rack?+
The bottom rack faces the lower spray arm and the heavy food. A blocked spray arm, a clogged filter or tall items blocking the arm cause it.
Should I pre-rinse dishes?+
Scrape off scraps, but do not rinse completely; detergent needs some soil to work with.
Can loading affect cleaning?+
Yes. Do not block the spray arm, and face the soiled sides toward the center.
How often should I clean the dishwasher filter?+
Every month or two, and more often if you see grit on dishes.