Standing Water in the Dishwasher — How to Clear It

You open the dishwasher after a cycle and there's a couple of inches of dirty water sitting at the bottom. Sometimes it drains a little when you open the door, sometimes it just sits there. The dishes might be partly clean or completely dirty.

This is one of the most common dishwasher problems I see in West Hollywood, especially in apartments where the kitchen plumbing was last touched in the '80s. About half the time you can fix it yourself in 20 minutes. Let's walk through it.

A note on a small amount of water

Modern dishwashers are supposed to leave a small amount of water in the sump (the well at the bottom) — usually less than a cup. This keeps the seal on the pump from drying out. If you see a thin layer of water, that's normal. If it's enough to splash when you open the door, that's a problem.

1. Clean the filter at the bottom

Every modern dishwasher has a filter at the bottom of the wash tub. Food particles, broken glass, fruit pits, even small bones get caught in it. When it clogs, water can't drain through it back to the pump.

How to find it: Pull out the bottom rack. The filter is usually a cylindrical mesh assembly in the center of the floor of the dishwasher, sometimes with a circular cover that twists off.

Remove it (most twist counterclockwise to unlock), rinse it under hot water with dish soap, and use an old toothbrush to clean out the mesh. Put it back firmly. Run a rinse cycle.

For Bosch and Miele units this is especially important — they're designed for users to clean the filter monthly, but most people in West Hollywood apartments tell us they didn't even know there was a filter to clean.

2. Check the drain hose

The dishwasher drain hose runs from the dishwasher up to the sink — usually high up under the sink before going down to either the garbage disposal or a separate drain stub on the trap.

The high loop is important. If the hose dips down before going up to the sink, dirty water from the sink drain can flow back into the dishwasher. If you don't have a high loop or an air gap, that can also stop the dishwasher from draining properly.

What to do: Look under the sink. The hose should go up to a high point (close to the bottom of the countertop) before going back down to the disposal or drain. If it's just a flat horizontal run, ask a plumber to add a high loop or — better — install an air gap. This is a building code issue in Los Angeles County, by the way.

3. Check the garbage disposal

If your dishwasher drains into the garbage disposal (very common setup in West Hollywood kitchens), the drain hose connects to a small inlet on the side of the disposal. When that disposal is partly blocked, dishwasher water can't get out.

Common cause: if you recently had a new garbage disposal installed, the installer may have forgotten to knock out the plug inside the dishwasher inlet. There's a small plastic plug on every new disposal that has to be removed before connecting the dishwasher hose. If it wasn't removed, the dishwasher cannot drain. Period.

Also: run the disposal for 30 seconds before starting a dishwasher cycle. Buildup in the disposal is one of the more common causes of slow dishwasher draining.

4. The drain pump itself

If the filter is clean, the hose is fine, and the disposal is clear, the drain pump in the dishwasher itself is probably the issue.

You can sometimes hear this — start a drain cycle and listen near the bottom of the unit. If you hear nothing, the pump is dead or its wiring is broken. If you hear a humming or grinding, something is jammed in the impeller (a piece of broken glass and a chip of bone are the two most common culprits we pull out).

Drain pump replacement: ~$220–$380 parts and labor. Bosch and Miele dishwashers run higher because the parts cost more.

5. Check valve issues

Some dishwashers have a small check valve on the drain pump output that prevents water from flowing back into the tub. When that valve sticks, water from the line slowly runs back in after a cycle. You'll see standing water that wasn't there when the cycle ended.

This is less common and usually requires a tech to diagnose — but it's a quick fix if that's the issue.

What it costs

Most dishwasher draining repairs run $180–$380. The high end is usually a Bosch or Miele drain pump or a control board. We tell you the part and labor cost in writing before starting.

When a dishwasher isn't worth repairing

Standard residential dishwashers (GE, Whirlpool, Frigidaire, KitchenAid) over 10 years old that need a major repair — drain pump plus control board, for example — usually aren't worth it. A new mid-range dishwasher is $700–$1,000 installed, and the new unit will be quieter and more efficient.

Higher-end units (Bosch, Miele, Thermador) almost always pencil out for repair because replacement is $1,500+ and the parts are designed to be serviced.