okay, now you're making me think back to that italian clockmaker that sydney went to in order to get that clock fixed back in the first season. remember how he made that curious remark about how rambaldi never told him what the clock was for, accidentally letting it slip that he may have personally known rambaldi? of course, this means that the clockmaker must have been alive for well over four centuries; but if rambaldi had some special medication/potion/formula/whatever that allowed allison to heal so quickly, then it may have also helped the clockmaker survive for so long.
and maybe this is what the water is. i don't know.