Hi Trackie and welcome to CP forums!
It depends largely upon where you plan to be using it. If you will be on a section of 'recreational designated' land (like Clear Creek or Cache Creek).... they can and do have rules, regulations, or permits regarding dredge use.
NF and BLM managed lands don't have dredging restrictions that I'm aware of as long as the land in question is open to prospecting/mineral entry AND unclaimed of course.