Hmm... Maybe, though I see some problems with it off the bat.
[REAGENT:water:150:LIQUID_MISC:NONE:WATER]
[REAGENT:water container:1:NONE:NONE:NONE:NONE]
[CONTAINS:water]
[PRESERVE_REAGENT]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
That
should take a container that has water in it as a reagent; it's a somewhat-modified version of the soap-making reaction's lye reagent lines.
The main problem I see is that this wouldn't actually tell your dwarves to go get water from a well, so you'd have to micromanage or engineer a way to get buckets of water some other way. Maybe if you put a pond zone on the far side of a one-way hallway such that dwarves went, got a bucket, went to the well, tried to get to the pond, found it inaccessible, and dropped the bucket you could automate producing water buckets...
It depends on how valuable the dyes are, I guess. It's certainly more realistic to have to grind the stones before dyeing things with them. Doesn't dye have to be a powder, though? So are you asking whether it's worth it to have the reaction go stone->dye instead of stone->powder->dye? Because I'd think just grinding the stone would be good enough; needing a second custom reaction, probably at a second custom workshop, to turn powdered stone into dye would be irritating, I think.