cory, sometimes talking to the school just doesn't work (and I know you know this, wrt other areas of need)
my dd has drinking issues (as well as other food issues) - thankfully a lot are now resolved, although she still doesn't drink enuogh.
at her worst, she was totally fluid-phobic - any wayer, in taps, puddles, the rain, baths - you name it, it was a problem.
her pre-school knew this, and yet that still didn't stop them putting a cup of water out for her, as part of their healthy eating initiative at lunchtimes.
the fall out was huge.
we fought, and won that battle. but her juice was kept away form her, and she had to ask for it (she wwas all but mute at school at this point), so that didn't work.
we changed schools, to a specialist pre-school. this one, despite freely admitting they couldn't cater for her special diet adequately, would not let us send in food for her to eat, as well as insisting on working on her water phobia, meaning again she was expected to drink water at lunch (when challenged on this - "but it's not fair on the other children, they want some too")
sometimes, you can talk until you are blue in the face, but it just doesn't get through, because the person you are talking to just thinks you are making a fuss, over-exaggerating, and that "if a child is thirsty they will drink"