Snake by the pool
Thank you for your question. Unfortunately, the head of the snake in these photos is out of focus, and I would feel more certain of the identification if I had a good image of the head. I believe this is an eastern milksnake (Lampropeltis triangulum triangulum). The eastern milksnake is non-venomous. They kill live prey by constriction. They feed primarily on rodents, but also eat lizards, other snakes and eggs. They are found in a variety of habitats including close to human habitation.
Typical length is a little over 2 feet, but maximum length is greater than 4 feet. They have a wide distribution in the U.S. and are found throughout Pennsylvania.
Here's a link to a site called PA Herp Identification where they have species descriptions and photographs of the species of snakes found in Pennsylvania:
Check out the photographs of the eastern milksnake to see if the head looks the same as the snake you found.
Hope this helps, and thanks for using Ask an Expert.