Usually if it is something no HoA I solve the issues but now the prolem is under the HoA mercy that seems to careless and the water damages are severe and scary on the photos.

Are you in a market where water lines could freeze in the winter if there’s no heat?

There's two 1500 gallon tanks.

That would burn through around 10,000 - 15,000 gallons in 24 hours.

Their fill hose sprung a leak or something and hundreds of gallons of water poured into the apartment below them.

Then wherever the water is getting discharged off of the roof, that what water is getting at least 4-5 foot away from the structure before it is left to drain with gravity away from the property. 

Water meter-water company.  

What if you turn on water and it goes everywhere.

So I've decided that due to poor caulking and grout condition of the upstair bathroom, I will cover the water damage, although the tenant did eventually cause more water damage.

Did nobody ever stop and say "oh, hey, maybe we should keep water pumps going because, ya know, no electricity no water pumping, NO WATER".