Dishwasher Not Draining? 5 Things to Check Before You Call a Pro
A dishwasher that runs a full cycle but leaves standing water in the bottom almost never means the whole unit has failed. It usually means something in the drain path is blocked, in one of five predictable places. Here’s where to check first.
Standing water at the bottom of the tub after a cycle is almost always a drainage blockage, not a broken dishwasher. The fix is usually somewhere in the drain path rather than in the machine itself, and most of these you can check in a few minutes before deciding whether to call someone.
Check the Filter at the Bottom First
Most dishwashers have a removable cylindrical filter at the bottom of the tub, under the lower spray arm. It traps food particles so they don’t recirculate, and when it’s clogged, water simply has nowhere to go. Twist it a quarter turn, lift it out, and rinse it under the tap. This single step solves standing water more often than anything else on this list.
A New Garbage Disposal’s Knockout Plug Was Never Removed
If a garbage disposal was installed recently and the dishwasher stopped draining around the same time, the two are connected. Disposals ship with a knockout plug blocking the dishwasher drain inlet, meant to be knocked out during installation. If an installer forgot this step, the dishwasher is pushing water into a dead end every time it tries to drain. This is one of the most common, and most overlooked, causes.
The Drain Hose Has a Kink or a Clog
The corrugated hose running from the dishwasher to the disposal or drain line can kink behind the cabinet, especially after the unit has been moved for any reason. It can also build up grease and food debris over the years like any drain line does. Pull the dishwasher out partway and check the hose for a sharp bend before assuming the problem is electrical.
The Air Gap or High Loop Is Blocked
If there’s a small chrome cylinder on the countertop near the faucet, that’s the air gap, and it’s designed to stop dirty water from siphoning back into the dishwasher. It also clogs easily. Twist the cap off and clear any debris. If there’s no air gap, the hose should instead form a high loop under the sink, and if that loop has sagged or collapsed, drainage slows or stops the same way.
The Drain Pump Itself Has Failed
If the filter is clean, the knockout plug is out, and the hose and air gap are clear, the drain pump motor may have failed, or a small object like glass or a bottle cap may be jammed in its impeller. This is the one cause on this list that usually isn’t a DIY fix, since it means removing the lower panel and testing the pump directly.
| Situation | What to do |
|---|---|
| Water pools around the filter | Remove and rinse the filter first |
| Disposal installed recently | Check for an un-removed knockout plug |
| Hose feels pinched behind the unit | Pull the unit out and inspect the hose path |
| Air gap or loop looks dirty or collapsed | Clear the air gap or re-form the high loop |
| None of the above help | Likely a failed drain pump, time for a technician |
If you’ve checked all of the above and water is still sitting in the tub, our dishwasher repair technicians can usually confirm whether it’s the pump or something further down the line in a single visit, including for the homes we service regularly around Bentwood and across San Angelo.
Frequently Asked Questions
Is it safe to run the dishwasher again if it didn’t drain?
It’s better not to. Running another cycle with standing water just adds more water on top of what’s already blocked and increases the chance of it overflowing onto the floor.
Why does my dishwasher drain fine sometimes and not other times?
That pattern usually points to a partial clog, something narrowing the drain path rather than blocking it completely, which is often the filter or the hose rather than a failed pump.
Can hard water cause drainage problems?
Indirectly, yes. Mineral buildup narrows the drain hose and coats the pump components over time, which is part of why older units in hard water areas drain more slowly even without an obvious clog.
How much does it cost to fix a dishwasher that won’t drain?
If it’s a clogged filter, hose, or air gap, there’s typically no part cost at all. A failed drain pump is a parts-and-labor repair, and a technician can usually tell you which situation you’re in during the same visit.
Need an appliance fixed in San Angelo?
Call (855) 677-0591 or request service online — most repairs are scheduled same-day.