What does water damage actually do?

Obviously it increases water damage. But it also increases healing on mages, right? Does it do the same on shamans too? And heals from the 'Rally' Major ID?

 

Yes, it increases all types of healing for every class including all of those. (Spells only though, it doesn’t affect things like life steal, hpr, and pots) It caps at 150% though so going past that doesn’t matter.
And yeah it increases water dmg too (but the dmg increases go past 150%, so u can still go past it if u want dmg)

 

Fun fact there used to not be a bottom cap, so immolation would cause you to slowly bring everyone near your totem to 1 hp