The following is a quick guide on how to deal with underground oils tanks "before giving a deposit" on a property. 1- The day you see a deal looks like it's a deal for you, order an oil tank sweep (which in north jersey costs around $200).

I am currently working a Full time Job as an Instrument & Electrical Tech for an Oil refinery.

over here in Vermont I pay about $3800 a year for oil heat on a 3 unit that has decent insulation. so $12,000 for 35 units seems quite low.

For heating... we keep three of the oiled filled electric radiator type on hand in storage, as they have proven to be the most safe and easy for our tenants to use. 

Paul Sandru does short term rentals for workers in the oil fields, I bet he has good advice for you.

Some had a one car attached garage.They also had a fuel oil furnace, asbestos siding and other issues to start off with. to begin with. 

The house has updated 100amp service, and a oil furnace.

A few impressions, memories.I recall hustling a bit more to get renters, but luckily my area was tied to oil prices which have been strong till recently.

I am not sure about the furnace, septic system and well and really don't know a whole lot about those sytems, but again should have a better idea once inspected.The $11K in expenses includes $4,600 in tax + $3K in oil + $2500 for insurance + Plowing and landscaping. 

Oil has plummeted.