Water moccasin and my 5 pound Chihuahua, what do I do?

I have a 5 pound Chihuahua and water moccasins everywhere. I live on 5 acres. I walk my dog on lead but I am afraid he might get bitten. What should I do? Kill the snake? I am very diligent. I do not kill snakes. I hate killing animals, but I do not want them to kill my best friend. Any suggestions??