I don't think this is particularly anti-mustachian, at least with the lifting thing. Lifting a 40-pound bottle (with the risk that you will spill several gallons of water on the floor if you don't swing it just right) is something a ton of adults can't do easily for a whole host of reasons that are not as simple as "not bothering to get in shape."* If manual labor isn't in my job description, I don't see why I should have to do that at work when there's a more convenient option. As to the money, I'm guessing your employer made a pretty mustachian choice to reduce the likelihood of 1) potentially-expensive property damage due to small floods and 2) potential workplace injuries if someone who is less physically able than you throws their back out or something lifting the bottle. If you like lifting 40 pound water bottles for the health benefits, grab one of the bottles that no longer needs to be lifted as high and pick it up for funsies.
I'd argue that a water bottle method isn't very mustachian at all, and that a better option is to have a water cooler/heater that connects to the water line, because you don't need to perpetually buy the bottles, and don't waste fuel and manpower delivering them every few weeks. (Tap water around me is fine, but it is pretty damn useful to have it automatically be hot or cold, and not waste time and energy on having an icemaker or some sort of kettle that needs to be cleaned by someone).
*among the possibilities: shorter than you, meaning the person has to raise the bottle higher on their body, a much more physically difficult task; pregnant; bad back; elderly; doesn't focus their "in shape" efforts toward upper body muscular strength (preferring instead to focus on cardio, lower body strength, flexibility/balance, whatever).