Portable toilets are illegal on Ontario waters.
The owner of a pleasure craft shall ensure that each toilet and the holding tank(s) is/are installed so that;
The toilet and equipment are connected in such a manner that the equipment receives all toilet waste from the toilet.
Equipment designed for the storage of human excrement is provided with a deck fitting and such connecting piping as is necessary for the removal of toilet waste by shore-based pumping equipment.
No means of removal of toilet waste is provided other than the means mentioned above.
All parts of the system for removal of toilet waste are congruent with one another and the boat.
That seems pretty explicit to me.
There is a Portable toilet that is Great Lakes legal. It has a vent and pump-out fitting. Sanipottie. If anyone would like one - I have a never-christened unit that I am willing to sell .... (in GTA)