Cat dander in carpet

[Bob Stein]

Hi all.

When in a property, I noticed that a tenant had an unapproved cat. I didnt mention anything. Now, they moved out and the new tenant said he's allergic to pet dander, which the carpet now has. I have to replace the carpet. The carpet was in the unit when I got it a year ago and is in ok condition. This is from the lease in the pet section:

"Tenant agrees to immediately pay for any damage, loss, or expense caused by their pet/s. Tenant agrees that any damage to the exterior or interior of the Premises, grounds, flooring, walls, trim, finish, tiles, carpeting, or any stains, etc., caused by the pet/s will be the full financial responsibility of the Tenant and that Tenant agrees to pay all costs involved in the restoration to its original condition. If because of any such stains, etc., said damage is such that it cannot be removed, then Tenant hereby agrees to pay the full expense of replacement."

The security covers full replacement. I was not planning on changing the carpet for the next few years. What should I charge them?

Thanks