Definitely a water snake and harmless! I have a rat snake that lives in my oak tree in my front yard for the past 3 years and it's about 6 1/2' long. Most snakes are good to have around let them be and they will just go on minding there own business.
I had 4 living around my house years ago. I would run across them from time to time, and just move them out of my way and continue on with whatever work I was doing.
I had one that took up residence in my well house. The first encounter was unexpected, it startled us both, but after that we both just went about our business and left each other alone.
I never had any rats in my well house.


