yep it could be just as likely that they enjoy building the dam whenever they hear water. seems much less stressful on the system

Evolution doesn't mind how it feels, it only matters if it's effective at adaptation. It could be that running water in their homes stresses them as much as it stresses us, albeit for different reasons.

The running water speaker experiment was done in dry land, and beavers are very wary of going out of the water because of their predators, yet they risked working over the speakers.