Tenant Rights of infestation in apartments complex

I live in an 8 apartment building. The entire building both sides are infested with ants. We have been getting a lot of rain recently and they are coming inside. It not just in one apartment, one side, or the lower level. The entire complex is having a problem. In the lease it states that the tenants are liable for any exterminator bills. Is this legal? My buddy ran into a problem with the rental agency put some clauses in his lease that wasnt technically legal, he beat them and didnt have to pay an extra $1,800 in alleged damages to his apt. Im just wondering if the rental agency is liable for the exterminator bill due to the entire complex being infested