Poly piping found...please help if you have knowledge this is in

[Constance Rappaport]

Well, it happened of course on Saturday night 1-2-21. Tankless water heater connect blew..was poly.  Water everywhere, and to make it worse I'm on top floor.  So my neighbor downstairs got a nice rain shower.  So my question is...I'm sure plenty of you have been thru this....just need to hear some stories.  My insurance is a commercial policy and I do not believe this will cover really anything at all.  Will the neighbor be sueing me?...checking with building insurance to see what they cover.  So far 2 plumbers been out...say it's a huge job, which I know.  Please share any info if you have gone thru this...Happy New Year!