The planned use for your RV will affect whether or not you need a CDL to operate it. The Federal Motor Carrier Safety Administration oversees the minimum requirements for the state issuance of CDLs for commercial motor vehicles. RVs used only for recreational purposes do not fall into this category.
Check with your state's department of motor vehicles to find out if you need a CDL, or another special license, to operate an RV that weighs more than 26,000 lbs., measures more than 45 feet or is towing a second unit like a boat. Each state has its own specific rules regarding this.
RV jargon can be confusing, and figuring out specific weights for CDL regulations can prove challenging. Online sites like Changing Gears offer information to help you understand RV weights and terms.