Tenant already in place and moving out a week after closing, security deposit

[Todd Michaels]

Hello,

I plan to close on a 2-flat in a month (week of June 22) with one unit vacant and the tenants in the other unit moving out the end of June.  We will be receiving their security deposit.  There is an issue with the tub in the occupied unit - the faucet of the tub leaks when the water is on and the leak hits right where the tub and wall tile meet, and of course there is no grout / sealant between the tub and wall tile so the leak goes directly below the tub.  The bathroom is on a slab foundation so there shouldn't be much of a problem with anything below the tub. 

So my question is, can I use the security deposit to off set the cost of fixing this issue?  Or as this issue is known when I bought the place, I can't use it for that and only for any damage done between closing date and the move out?

The lease is month to month and I do not know if the tenants even told the current owners of the problem.

Thanks.