I have two siberian huskies that love to go swimming in the pool. They have never hurt the liner, but we have built in steps that they use with no problem. I had a tech come work on my hidden fence (keeps the dogs on the property) and he brought his lab with him. That dog was amazing. He would jump about four feet in the air and dive into the pool. What was amazing was he did not use the steps to get out, he knew how to climb the ladder! Now that is some smart dog.