Our cat was using a corner of our landing which is carpeted for peeing and we did not notice for ages....until the smell. That was nearly two years ago. During the winter months we dont get a smell but now that the summer is here, you can get the smell when u go upstairs. We cannot afford to replace the carpet as it is an expensive one....it has been washed by professionals, soda powder etc....the smell is still there....has anyone any other ideas....ta!!