This sounds terrible and I personally know how bad this type of noise can be, but it can be stopped I’d reckon.
Have you spoken to the resident to ask what gives and about your concerns? Why this water is running is the obvious question. Are they an owner or tenant and which are you?
Have you mentioned this to the building’s Owners Corporation’s Executive Committee?
You say ‘strata’ wrote to him; who exactly wrote to him and who complained to strata? Is this a problem for other neighbours too?