What does Bosch Washer Won't Drain - Causes & Fix mean?

A clogged drain pump filter or kinked drain hose is usually the cause. Clean the filter and inspect the hose for blockages or kinks.

How do I fix Bosch Washer Won't Drain - Causes & Fix?

Work through the step-by-step fix below. Start with the quick reset and the most common cause, then check the specific part this guide points to. Most fixes need only basic hand tools and the right replacement part.

Can I keep using my Bosch appliance with this error showing?

Usually not. Bosch appliances show this error when a part or safety circuit is out of range, so running it can stop the cycle or make the problem worse. Diagnose and clear the error before normal use.

What part is most commonly replaced for Bosch Washer Won't Drain - Causes & Fix?

The parts that most often fix Bosch Washer Won't Drain - Causes & Fix are listed in the parts section of this guide. Match the part to your exact model and serial number before you buy.

Is Bosch Washer Won't Drain - Causes & Fix a DIY repair or do I need a technician?

Many fixes are DIY-friendly with basic tools, such as door switches, drain pumps, water inlet valves, thermostats, heating elements, and filters. Sealed-system, refrigerant, gas, or high-voltage work should go to a licensed technician for safety.

Bosch Washer Won't Drain - Causes & Fix

Bosch Washer Won’t Drain — What’s Happening

When a Bosch washer won’t drain, the machine has failed to pump water out within the expected time. On most Bosch models this corresponds to a drainage fault like error code E18 or F18, though the symptom can appear without a visible code. The washer may stop mid-cycle with water standing in the drum, or it may complete the wash but refuse to spin because water is still present.

Bosch groups this problem under blocked drain paths or pump maintenance issues. The machine’s control board expects the drain pump to empty the tub within a set window. If water remains, the cycle halts to prevent flooding or damage. The fault is almost always mechanical (a clog, kink, or failed pump) rather than electronic.

Jump to Fix

Most Likely Causes

Clogged drain pump filter or coin trap Lint, coins, buttons, hairpins, and other debris accumulate in the pump filter housing and block water flow, preventing the pump from evacuating the tub.
Kinked or blocked drain hose The flexible drain hose can kink during installation, get crushed behind the machine, or develop internal blockages from lint and soap buildup.
Blocked external drain pipe or siphon The standpipe, wall drain spigot, or under-sink trap can be clogged with household waste, restricting or stopping outflow even when the washer’s pump and hose are clear.
Jammed or failed drain pump Foreign objects can jam the pump impeller so it cannot spin, or the pump motor itself can fail electrically and stop running even when commanded by the control board.
Blocked sump hose between tub and pump A short internal hose connects the tub sump to the pump inlet and can trap socks, small garments, or debris that bypass the tub basket, choking flow before it reaches the filter.
Defective pump wiring or control board signal Loose connectors, broken wires, or a control board fault can prevent voltage from reaching the drain pump, though this is much less common than mechanical blockages.

How to Diagnose and Fix

Unplug the washer from power and turn off the water supply valves to make the machine safe for service.
Locate and remove the drain pump filter (usually behind a lower front access panel or kick plate), catch residual water in a shallow pan, and clean out all debris from the filter and housing.
Inspect the pump impeller through the filter opening by shining a light inside and turning the impeller by hand to confirm it rotates freely and is not jammed by foreign objects.
Pull the washer forward and inspect the entire length of the drain hose for kinks, compression, or damage, then disconnect it at both the pump outlet and the wall connection to check for internal blockages.
Check the external drain path by pouring a gallon of water directly into the standpipe or sink drain connection to verify the household plumbing can accept full flow without backing up.
If the filter, hose, and external drain are all clear, remove the lower front panel or tip the machine to access the sump hose connecting the tub to the pump, then disconnect and inspect it for lodged debris.
Test the drain pump electrically by running a drain or spin cycle (with the machine reassembled enough to be safe) and using a multimeter to verify the control board is sending voltage to the pump terminals when the drain command is active.
Replace the drain pump assembly if voltage is present but the pump does not run, or replace the drain hose, sump hose, or filter housing if any of those components are damaged or remain obstructed.

Parts You Might Need

Part	Notes
Bosch washer drain pump assembly	Amazon \| Includes motor, impeller, and outlet fitting. Verify your model number before ordering.
Drain pump filter and cap	Amazon \| Replace if the filter housing threads are stripped, the cap seal leaks, or the filter itself is cracked.
Drain hose	Amazon \| Order the correct length and diameter for your Bosch model. Most are ribbed flexible hoses with clamp fittings.

If your appliance also shows a code on the display, these match this problem:

When to Call a Pro

Call a technician if you have cleaned the filter, inspected all hoses, verified the external drain is clear, and the washer still will not drain. If electrical testing shows no voltage at the pump during a drain cycle, the control board or wiring harness may be at fault and requires diagnostic tools and schematic knowledge. A pro can also handle pump replacement quickly if access requires significant disassembly or if you are uncomfortable working with live voltage tests. If the machine is still under warranty, contact Bosch service directly before performing invasive repairs.