There is an RV park in Monticello as you're coming into town from the Moab area that I've dumped at before for a 5 dollar fee. Can't remember the name of it but it's right across from the Rodeway inn motel. Blanding also has an RV park that will let you dump for a fee but I've only stayed there, not stopped to dump only. Not any city/public places to dump that I'm aware of other than the commercial RV parks unless you hit the one in canyonlands.
2015 Ram 3500 Laramie CTD, 4X4, AISIN, B&W Companion Puck Mount
2016 Heartland Bighorn 3270RS, 1kw solar with Trimetric and dual SC2030, 600 watt and 2k inverters.