No I mean drinking water from the faucet or bottled water that is the cause of her allegy. The water in her spit and mucous membranes does not make her sick.
If she is allergic to water from a tap or a bottle but not to the water inside her body, then she is not allergic to water. She is allergic to something else in the water. I think we have already covered this.
I seriously suggest you and OP go and research how allergies work... My bf is allergic to wheat protein, it doesn't matter what form the wheat protein it is, raw wheat, flour products, glucose syrup made from wheat (because the gluten is removed but it's a bigger molecule than the one he is allergic to) it doesn't matter. If he eats that protein he has an allergic reaction. To be allergic to water is to be allergic to blood plasma, saliva, mucus, urine, sweat, and even the mucus that helps you poop.
She could have an allergy to ptfe plastic residues, which are found in both drinking water ( pipes) and bottled water ( bottles and storage tanks) she'd have to be incredibly sensitive to them though because levels are low She'd only be able to drink distilled water , or rain water which had been kept in glass or metal containers That would medically plausible but unlikely...
But drinking water is water. It's not a different compound from the water in her body or bathing water. If she's allergic to one she'd be allergic to all, and she'd therefore be dead.
Depends on your definition of "seriously". Do I believe that the story concept, in any form whatsoever, is worth talking about? No. Do I believe that anyone can really believe that a human can be allergic to water, or that the water in saliva or a bath tap is fundamentally different from that in a drinking tap? Not sure. If someone did believe that, would I care? I shouldn't.
Plot twist: What if all of us are the ones who are diseased and water is actually bad for us, but we drink it because our disease makes us think that we need it. This girl is the only one who sees the truth, but she's seen as a freak because she can't interact with water. Also, the water is voiced by James Earl Jones.
People with this condition are borderline psychopaths (not a psychologist, but just from what I've observed in this condition), as they are chronic liars and have a habit of stealing medication., even though its not needed. I'm not sure on the specifics on how people with this condition get the medication, if OP wants to go on the munchausen by proxy route, she may need to research it for herself. If she'd like, I' could probably find something myself. As for the "no one would believe her" part, most doctors don't believe the victims are sick, which is why the caretaker goes through such extremes.
Because it's obvious to anybody with medical training (or common sense) that being allergic to water is absurd.
Water accounts for, on average, 60% of a human's anatomy and 73% of a newborn's, to be allergic to the water molecule is to be allergic to something that makes up major organs of the body: Heart: 73% water Lungs: 83% water Skin: 64% water Muscles and kidneys: 79% water Bones: 31% water Saliva: 97% water Blood plasma: 92-95% water And this is before I drag up my previous post highlighting that such a person would go into shock every time she peed, got sweaty, or took a dump. This is why the poll votes are unanimously 'no', this is why there are seven pages of people disagreeing with OP and cracking jokes at their character's expense, myself included.