What if you sale your rental house while tenants are in there.

Is there a contract or other written agreement, and if so, what does it, say? For example, is the tenant's occupancy "at will," which means that it's only for long as they want to stay and you let them? Is it month-by-month, in which case they can stay through the end of the month? Is it a yearly rental, in which case they would, as long as they uphold their end (pay rent, don't trash the place, etc.), they would normally be able to stay through the end of the year?

Assuming there is a written lease, which is a contract, and there's a defined lease term--be it month to month or for a year--then you have a legal obligation to them for whatever the term of rental is. If you sell the house while the tenants are there, either (1) the new owner can take over the lease, in which case it--and its obligations--are transferred in writing to the new owner, and you're off the hook; or (2) you will have to compensate the tenants in some way for moving them out ahead of time. That will presumably involve paying costs associated with finding and moving to a new place, including possibly any difference in rent (if they end up paying more) for the balance of the lease. The important thing to remember is that regardless of who owns the whom, if YOU signed a lease/contract, YOU are the one who has the obligations.

If there is no lease, then normally the rental will be assumed to be month to month, which means that the tenants' right to stay has to be "renewed" each month. In that case, best thing to do is to time the closing on the house to be the first of a new month, and to have given you tenants prior notice--a month's notice if you can--that you will be selling the house and their tenancy is coming to an end. If you can do that, there's no other obligation to them.