Can I deduct bathroom water damage from security deposit?

[Jason M.]

My tenant just moved out recently and I discovered water damage under the floor of a bathroom. I don't have a "before" picture proving it wasn't there before hand. However, I do know that the tenant was caring for small children during her stay which would have resulted in a lot of baths for kids and lots of overflowing or splashing water from the tub.

I'm lucky the sub floor is two layers with a 3/8" top layer that I can tear off. The pic below is after I tore up the top layer and did a quick wash with bleach and water on the bottom. The lower layer is not as bad, and may clean up with some more bleach treatments but overall I'm going to have to replace part of the sub floor. 

I may just rip up the cheap laminate and tile the whole floor with a decent ceramic/porcelain tile to prevent this from happening in the future (plus it'll just look 100% better), but I realize that will be my cost and not the tenants.