Repair guide
Dishwasher Not Draining: What to Check
Updated 10/11/2026
A little water under the filter is normal: it keeps the seals wet. Water standing above the filter after a cycle is not.
Very often the cause is a blocked filter or something under the sink, and you can clear it yourself. This guide says plainly where that ends and a repair begins. Mend My Appliance repairs dishwashers at home across the Portland metro area.
Before you check anything
- Switch the dishwasher off at its breaker before you reach into the tub or work under the sink.
- Standing water can hide broken glass. Scoop the water out with a cup and feel with a wooden spoon before you use your hand.
- Do not pour drain cleaner into a dishwasher. It damages the pump and the seals.
- Do not remove the kick plate or the door panel.
What you can check yourself
The filter
Twist out the filter in the floor of the tub and rinse it under the tap with a soft brush. Many newer dishwashers have a filter that needs cleaning by hand every few weeks; older ones grind the food up and have no filter to take out. Look into the well under the filter for glass, seeds and labels.
The garbage disposal
The dishwasher usually drains through it. Run the disposal before you start the dishwasher. If the disposal is new, the plug in its dishwasher inlet may still be in place; ask whoever installed it to remove it.
The air gap
If you have one, it is the small cap on the sink next to the faucet. Lift the cap and clear what has collected inside. Water coming out of the air gap while the dishwasher drains means the hose between it and the disposal is clogged.
The drain hose under the sink
It should rise in a high loop to the underside of the counter before it drops to the drain, and it should not be kinked or crushed by what is stored in the cabinet.
The sink drain
If the sink itself drains slowly, the dishwasher has nowhere to send its water. Clear the sink first.
The cycle
A cycle that was interrupted, by an opened door or a power cut, leaves water behind. Close the door, start a cancel or drain cycle and listen for the pump. The manual says which buttons start it.
Standing water in the bottom of the dishwasher
A cup or two of clean water sitting below the filter is there by design. Dirty water above the filter at the end of a cycle means the drain step failed. If the water is there before a cycle starts, it is coming back from the sink: the high loop is missing, or the disposal is backing up into the hose.
Dishwasher hums but does not drain
The drain pump is running, or trying to, and no water moves. Something small (a shard of glass, a fruit pit, a twist tie) has jammed the pump, or the pump has failed. Both are repairs: the pump is reached from underneath.
Draining slowly and washing badly
A dishwasher that drains poorly also washes poorly, because the dirty water is never fully replaced. If the dishes come out gritty as well, clean the filter and check that the spray arms turn freely before anything else.
What usually fails
- Drain pump: jammed or worn out.
- Drain hose: clogged with grease, or kinked.
- Check valve: stuck open, so the water runs back into the tub.
- Drain solenoid, on some older models.
- Control board: the drain step is never started.
When to call for a repair
- The standing water comes back after the filter, the disposal and the hose are clear.
- The dishwasher hums at the end of the cycle and nothing drains.
- Water leaks at the door or shows under the dishwasher.
- It will not start, or will not finish a cycle.
- The same error code keeps coming back.
What a repair visit involves
- Book online: choose the appliance, describe the problem and pick up to three times that suit you.
- We confirm one of your times by phone or text. You are not booked until we do.
- We come to your home, test the dishwasher and find the cause.
- You get the price before any repair begins. We repair it with your approval; if a part has to be ordered, we come back to fit it.
The diagnostic visit costs $90. If you go ahead with the repair, the $90 is applied toward it; if you decide not to repair, the $90 covers the diagnosis.
Our work and the parts we install carry a 90-day warranty. The terms are printed on your invoice.
Repair the dishwasher or replace it?
It depends on the age of the dishwasher, the cost of the part and what a comparable new one costs. A diagnosis gives you the numbers for your machine, and the decision stays yours.
Where we work
We come to homes across the Portland metro area in Oregon, among them Portland, Beaverton, Hillsboro, Tigard, Tualatin and Lake Oswego. Enter your ZIP code when you book and the form checks it right away.