Who is responsible for clogged bathtub?

[Alex Rodriguez]

I bout a property 1.5 years ago and inherited these tenants. That are bad and dirty tenants. I made the mistake of letting them stay. Anyway, one of the first things I did was to replace the bathroom ceiling, which was in bad state. This was 1.5 years ago. Now they are saying that since then, because the contractors didn’t cover the drain, dust got in and the tub has been slow moving. I just got the complaint today 1.5 years after the work was completed!.

I have this on my lease: "Tenant accepts the cost of clearing the drain of any and all stoppages within the property except those caused by defective plumbing, tree roots, or act of Nature or God." I offered the tenant to hire a plumber, but unless it’s a defective plumbing issue like corrosion, they will be responsible for the cost. She said it was unfair because there could be something that traveled from the tenants above them (it’s a 3 story 3 unit building). I don’t think that would be possible and told her that. She said it’s unfair because hairs can pass through the drain cover over time too. And lastly said that she will figure out how to fix it.

But I’m worried because I don’t know if it’s possible that she can break the plumbing trying to use a snake, or using too many chemicals? Should I hire a plumber and bill her (if it’s a clog) regardless of her not wanting to? Can I claim that not fixing it could cause more damage to the property?