You need to check with your local DMV.
I have been told I don't need one here in VA by several on this site, and it seems that is true by the wording of their rules.
But according to DMV, I still have to go across the scales because my vehicles gvwr is over 7500 lbs.
I also had a DOT employee tellme if either of my vehciels had a gvwr over 10,000 lbs i had ot have a CDL.
If your GCWR is over 26,001 lbs, or if you are doing it as a job (commerce), you need a CDL. GCWR is the gvwr for your truck + the gvwr for the trailer added together. They can not total more than 26,001 lbs.
Some states don't enforce the 26,001 lb limit if it is a personal vehicle tho. That's why I said check your local DMV, and I'd check in at a weigh station just to make sure. That's what I'm gonna do. if they tell me I don't have to stop, then I won't.
Good Luck finding out a straight answer tho.
Mark