An old fashioned groover (jus a rocket box with a trashbag) doesn't cut it - no human waste allowed in the trash. I used to always just designate one of my Nalgene bolttles as an emergency groover (NOT reuseable
), but that doesn't work. Neither does a medium sized tupperware container. I also used to put my lunch in a tupperware box, and designate it as an emergency groover if needed. That doesn't cut it anymore, either. So, he'll most likely check that you have an "approved" one. Unfortunately, there isn't a really cheap solution. If there are any rafters, get a large system, the tank fits in a rocket box, and a seat attaches. There's a RV-type kit for emptying it. If jus kayaks are going, there's a smaller kit that will BARELY fit in the stern of a playboat.
I don't know if they can be rented...call around I live here in GJ, I s'pose you could use mine...email me your info...
You can empty them for free at the Fruita visitors center, otherwise it costs you (yes, you have to PAY for the pleasure of cleaning up other people's sh*t) like $8 at an RV park.