I am looking to buy a single family house for a fix and flip in Bergen County, NJ. The seller told us there is a tenant who has illegally been living in his basement for the last 12 months. The property is not zoned as a two family. Legally, how can I evict him and how long should I expect that to take? This is the only issue that preventing me from closing on the project. Is this issue a deal breaker?

Can you put in the contract that property is to be delivered vacant and let the seller deal with getting the illegal tenant out?

Are you in contract yet? YOu can either have seller evict before contract signs and delay everything for closing until that is over.. Or you can file for eviction as soon as you take over the property.

What type of lease is there for this tenant, if the owner was renting to him and he mostly used the  basement knowing he was not following zoning then it's really owners responsibility to get rid of the person. IF he was a ROOMMATE and was living WITH the owner, and was  mostly using the basement then the owner wasn't doing something totally wrong. Just offer the guy $$ to move out as soon as possible and get the house under contract if you want the house.

If he has a lease the you have to have either the owner give proper notice, and he's gone prior to closing, or you have to give notice after you close, and give proper notice for non-renewal and if he doesn't cooperate then you file eviction.. NEGOTIATE get it done get him out. 

I wouldn't say deal breaker just figure costs for court fees and not having full use of the building until tenant is gone.