The OP is in the Chesapeake area, not the northeast.
Doesn't matter, most pumpouts don't happen here in the winter either - creeks are frozen and you can't move your boat to the pumpout, or the pumpout boat to you. Except for dockside services at $30 or more per pumpout (yikes!). Otherwise you use a bag and a bucket, or use the marina heads. (Or discharge illegally which I'm NOT recommending)