Dishwasher Not Draining? Three Things to Check Before You Call

Your dishwasher finishes a cycle, you open the door, and there’s standing water at the bottom. Maybe an inch. Maybe more. It smells like last night’s dinner, and you’re wondering if this is a simple fix or a call to a repairman. Last year alone, I cleared a clogged filter on a Whirlpool in Lewisville where the owner had been scooping water out by hand for two weeks—thinking it was a broken pump. It wasn’t. Nine times out of ten, the issue is in one of three places you can check yourself in about fifteen minutes with no tools. Here’s what to look for.

1. The Filter Basket

Every dishwasher has a filter assembly at the bottom of the tub, right under the lower spray arm. On most Whirlpool, Maytag, and KitchenAid models, it’s a cylindrical mesh basket you can twist and pull out. On LG and Samsung machines, it’s a flat screen that slides out. Food particles, broken glass, and even small plastic bits collect here over time. If that filter is clogged, water can’t pass through to the drain pump.

Pull the filter out and rinse it under hot water. Scrape off any debris with your fingers or a soft brush. If the filter looks clean but the water still won’t drain, put it back and move to the next step. What this check tells you: if the filter was packed with gunk, you just fixed the problem yourself. If it was clean, the blockage is further downstream.

Cost reference: A new filter basket runs $10–$20 at most hardware stores. Our service call to check it is $89—but you just saved that by doing it yourself.

2. The Drain Hose

The drain hose runs from the dishwasher to your sink’s drain line or garbage disposal. It’s a corrugated plastic tube, usually about 5/8 inch in diameter. Over time, grease and food sludge build up inside that hose, especially if you don’t run hot water through the sink regularly. A kink in the hose can also stop drainage cold.

Pull the dishwasher out from under the counter—it’s usually on adjustable feet or small wheels. Trace the hose from the dishwasher’s drain pump to where it connects under the sink. Look for sharp bends or crimps. If you see one, straighten it out. If the hose looks clear, disconnect it at the sink end and drain it into a bucket. You can blow through it to check for blockages. If air won’t pass, the hose needs to be replaced. What this check tells you: a kinked hose means you just saved yourself a service call. A blocked hose means you need a new one, which is a cheap part but a pain to swap without pulling the dishwasher all the way out.

Cost reference: A new drain hose costs $15. Our service call is $89—and if you need us to install it, we’ll quote you the labor upfront.

3. The Garbage Disposal Connection

This is the most common cause I see on dishwasher repair calls in The Colony and Highland Village. A customer in Frisco once called me out because her dishwasher wouldn’t drain for three months. She’d already replaced the filter and the hose. I looked under the sink, took out the knockout plug with a screwdriver—took maybe ten seconds—and the machine drained immediately. She’d had a new disposal installed the year before, and the installer forgot to punch out that plug. Most dishwashers drain into the side of a garbage disposal. That connection has a rubber knockout plug inside it—a small plastic or rubber disc that seals the disposal port during manufacturing. If you or a plumber installed a new disposal and forgot to knock that plug out, your dishwasher will fill with water and never drain. It’s a dead-simple mistake that stops everything.

Look under your sink. Find where the dishwasher drain hose connects to the disposal. If you see a plastic cap on that port that looks like it should be removed, take it off with a screwdriver. If the hose connects directly to the sink drain pipe (no disposal), check for a high loop or air gap on the countertop. A clogged air gap does the same thing. What this check tells you: if you find that knockout plug still in place, you just fixed your dishwasher in thirty seconds. If the connection is clear, the problem is likely the drain pump or control board.

Cost reference: Fixing a knockout plug is free—it’s just removing a piece of plastic. If you need a new air gap, that’s about $12. Our service call to diagnose it is $89.

Preventive Tips

Once you’ve got the water out, keep it that way. Two simple habits cut drain issues in half:

• Clean the filter monthly. Pull it out, rinse it under hot water, and scrape off any buildup. Set a phone reminder—it takes two minutes.
• Run a hot water cycle once a week. Fill a cup with white vinegar, set it on the top rack, and run the hottest cycle. This breaks down grease inside the drain hose and keeps the pump clear.

When to Stop and Call a Professional

If you’ve checked all three of these and your dishwasher still isn’t draining, you’re looking at a failed drain pump, a stuck impeller, or a faulty door switch that’s telling the machine the door is open when it’s not. These are not DIY jobs. Replacing a drain pump on a Bosch or Samsung requires pulling the dishwasher out, disconnecting the water supply, and working with electrical connections. One wrong move and you flood your kitchen or short out the control board. That repair goes from a $250 pump replacement to a $600 control board replacement real fast. (See our Bosch drain pump replacement guide here for what that job actually involves.)

Here’s a quick comparison to help you decide:

| Fix | DIY Time | DIY Cost | Pro Repair Cost (incl. service call) | |—–|———-|———-|————————————–| | Clogged filter | 5 minutes | $0 | $89 (service call only) | | Kinked drain hose | 15 minutes | $0 | $89 | | Blocked drain hose | 30–45 minutes | $15 (new hose) | $89 + $45–$75 labor | | Knockout plug still in place | 30 seconds | $0 | $89 | | Failed drain pump | 1–2 hours (if experienced) | $50–$120 (part) | $89 + $150–$250 labor | | Control board issue | Not recommended | $150–$300 (part) | $89 + $200–$400 labor |

That’s where S&W Service & Repair LLC comes in. We handle all the brands you probably have in your kitchen—Whirlpool, Maytag, GE, LG, Samsung, KitchenAid, Frigidaire, Bosch, Kenmore, Sub-Zero, Wolf, Viking. If you’ve got an Old Republic Home Protection warranty, we take those work orders too. We cover the whole North Texas area from Denton to Plano, including Little Elm, Oak Point, Frisco, Lewisville, Highland Village, Flower Mound, The Colony, Krum, and Crossroads. No upselling, no fluff. We show up, diagnose it, and tell you what it’s going to take to fix it.

If your dishwasher isn’t draining and the simple checks above didn’t solve it, don’t let it sit for a week. Standing water breeds mold and can damage the door seal. Give us a call at 940-286-4094 or book online at our Setmore link. We’ll get it sorted.

Need appliance repair in North Texas? Book a service appointment or contact the S&W team and we’ll get your appliance running again.