Cracked bathtub - Wear & Tear? Tenant Vs. landlord pay?

[Sammy Msouty]

Tenants say there is a water leak. We go to the upstairs bedroom and the bathtub has 4 cracks that are clearly leaking water. The cracks are so extreme that it almost looks like the bottom is going to fall out because they create a nearly complete semi-circle around the edge. 

No one informed me and one of the tenants admitted to seeing it at least 4 months ago.

My question is can I claim it is not wear and tear and that they are responsible for it? I would guess the tub was installed 10-15 years ago and is likely fiberglass. I do not know if there is adequate support underneath and that it was installed properly.

If it is considered normal wear and tear then can I charge them for the water damage since they didn't report it in a timely manner? I have language along those lines in the lease.

Thank you.

PS, I live in Indiana.