After further research I am modifying my asterisk on the water containing item to "May"
For further details I need to do more research.
However, there is no apparent change in the water level of a canteen repetively done totem on, however towel which totem is done on becomes dry. I will test some other ultra-cheap but unpractical containers (vials from the Alchemists guild, for instance.)
If someone has a poison container they could fill with several ounces of water to test, that would be useful.
I will also find some time to do further experimentation on volume of water needed, and with more measurable ammounts of water than 2 pints (the capacity of my canteen). I will also check differences between an open and closed canteen.