If I was the tenant that got damage from another tenant's water heater, I would expect him to pay the bill.If it was a pipe in the building and not in their unit, then I would think the landlord would be responsible.

Inherited tenants are usually a negative, however in that area leaving the duplex totally vacant makes it a target for thieves to come in and steal your pipes, furnace, and hot water tanks.

Water/sewer is shared and can be sub-metered. 

Don't forget about paying to start electrical, gas, water and internet services.

It is best to run a new electrical line to the unit that has the water and only allow that unit to use the W&D. 

Other campsites are truly primitive with no amenities at all in terms of water/power/sewer. 

If separate water line services for each unit weren't part of your original scope of service, then they are justified in asking for additional payment to redo the plans.

I work in the yachting industry and love being on the water.

Go and find out because the first thing you want to do is get the water out and dry out the space.

I think that this is the "blood in the water" thing that investors talk about. - The examples have incredibly good math on paper.