Arson in the second degree is defined (in my state) as starting a fire or causing an explosion and it causes damages of more than $750.
So yes, if the water causes a fire or explosion, it can meet the definition of arson.
The business record exception to hearsay (ORS 40.460). I don’t generally use this rule, but when dealing with financial cases with a multitude of documents, it is very useful.
Learned about it at law school and work.