What causes a washing machine to not drain?

When a residential washing machine fails to drain wastewater at the end of a cycle, leaving the drum full of water, the malfunction is typically caused by a clogged drain pump filter, a blocked external drain hose, a failed drain pump motor, or a jammed pressure switch. Over time, lint, coins, paper clips, and small garments can slip past the drum baffle and lodge inside the pump filter, preventing the impeller from spinning and forcing water out. You can troubleshoot drainage easily by checking the pump filter compartment behind the lower service access door. You can verify that your corrective action is successful when clearing trapped debris out of the pump filter, straightening kinked drain hoses, or replacing a burnt-out pump motor allows the machine to empty the drum completely.