Dirty water is leaking from underneath the machine; what would be the most likely problem?

The presence of dirty water leaking from underneath the machine is most likely indicative of an issue with the waste pipe. When the waste pipe is blocked, water cannot flow through it as intended, causing it to accumulate and overflow from the drip tray box. This buildup of liquid leads to spillage and gives the impression of a leak.

Understanding the mechanics of the machine is crucial in diagnosing such issues. If the waste pipe is obstructed, it prevents proper drainage, which can result in water backing up and leaking out. In contrast, a malfunctioning machine could potentially lead to other types of issues, but is less directly associated with the specific scenario of dirty water leaking out. Similarly, needing to turn off the water supply or needing a new filter may be necessary for maintenance or other functions, but they would not directly cause the observed symptom of leaking.

Identifying that the waste pipe is blocked provides a direct route to resolving the problem by clearing the blockage, ensuring proper drainage, and preventing further leaks.