The smoke cloud is not visible in the water. I don’t know if there is any way to make it visible. Is there a way, or does Eevee not support anything like this at all?
Note that this is in Blender 2.81 because for this particular render I made it a while back and I want to render it again. I tested volumetrics in 2.83 and it still doesn’t seem to work anyway.
If it can work in any later version, that would be good to know if it does become the only option. I could probably reference the same bake files that it is located in.
With EEVEE you want to make sure to have reflection plane light probe and set volumetric render clipping settings to as large as the longest reflection desired. See if that helps
…But now we can convert the Volume to Mesh, in 3.4 using geometric nodes, and we can now have a low-res geometry clone of the volume, inside of it, that will show up on the reflections.