Using water invites mold, this is one of the main issues the australian government complains about in regards to their black market tobacco, 'chop-chop'. My father made the same mistake with his herb, he would use lemon rind and his herb would get all moldy, then his stubborn ass would smoke it anyway
Not healthy.
Proper rehydration employs controlled elevated humidity above ambient humidity but well below 100%. IIRC 65% humidity is what is used in curing tobacco to keep it flexible and curing, but not moldy. In tobacco shops you'll see little machines with propylene glycol solutions in the cigar cases for maintaining a controlled humidity.
If you have a CRC the 'constant humidity' section is useful. It uses a mix of a chemical and its saturated solution to form a constant humidity environment in a closed container for softening your herb in, it just takes a few hours to overnight.
Ammonium chloride produces 80-78% RH at 20-30° C
Ammonium sulfate (a fertilizer) produces 81% RH at 20-30° C, this is what I used for softening smokes and cigarettes in a few hours.
Sodium carbonate (washing soda, oven-baked baking soda) produces 92% at 18.5°C and 87% RH at 24.5° C this is too high but will rehydrate faster.
Magnesium acetate is probably nearest to ideal for longer term storage at 65% RH at 20° C
Dont let the chems touch your herbs.
A tobacco smokers trick is to dunk a piece of newspaper under water and tightly ring it out before putting it in a closed container with tobacco for a couple hours, its done only for what will be smoked that day, its taken out after an hour or three, since it can cause mold.