Is it a mechanic's lien you are looking to record?  

I own a beauty parlor, nail salon, auto mechanic and auto detailing shop all with a 10 year leases.

Were you able to verify length this tenant has been at this property, what is condition of mechanicals , how old is the roof .

So don't loose sleep about loosing money on the property.Take maximum advantage of the home owners warranty as it applies to all the mechanical systems & appliances.  

Find out why seller is selling, ask for a rent roll, what repairs or updating of mechanicals and roof has been done, how long seller has owned the property, are there pets allowed, are taxes current, has there been any insurance claims where seller did not use money for the repairs, ask for sellers disclosure, are there separate water and electric meters, does rent include utilities or not, are there long term leases or month to month, does deposits transfer to new owner, if there is pets, is the deposit a fee or deposit.

@Sylvia B.I will walk you through my understanding using the 2015 rules and assuming that this is the only activity you had in 2015.The mechanics of the computation are based on taxable income.

Read books about investing and managing properties, but also go on youtube to learn about the mechanics of the property.  

They cannot obtain permits for plumbing, electrical, and mechanical work.  

I work for a firm that does Mechanical/Electrical/Plumbing Engineering work, primarily for architects and developers.  

Unless you purchase a property where 100% of all the mechanical systems  or major elements like the roof are new, you may need reserves beyond the $7K required by FHA.