My inlaws live in Bonham, which is about half an hour from Sherman. My mother-in-law doesn't know for sure if their plumber works in Sherman or not, but she said they're really good- CK plumbing. (903) 640-8700 or 1 (903) 227-0972. She said using their names (Kelly and Lee Ann Kemp) would probably help. I hope they work in Sherman and can help you out!