They will get a $100,000 liability to cover fires, water damage, accidents, and more.As @Greg Scott stated, you should require your tenant to add you as "additional insured" on their policy.

What happens when the water service line has to be replaced?

If you can get a house with a killer view I think that is what sells the most, second being on water. 

I’ll give the water company a call on Tuesday.

Water submetering is more difficult with smaller properties; especially older ones. 

All of that is going to be very helpful while navigating new waters.

The good applicant eventually gets tired of carrying the water for the other, leaves, and you are stuck with a bad tenant. 

I normally recommend using a Property Manager who works with the program regularly to help navigate the waters. 

Each unit has its own electric panel, gas meter, furnace, water meter.

I'd also look to see if water is getting in or if it was just a problem with humidity.