Does your employer have to provide drinking water within a certain distance from your work area? I work in a different building from the nearest drinking fountain
Per T8CCR 3395(c):
The water shall be located as close as practicable to the areas where employees are working. Where drinking water is not plumbed or otherwise continuously supplied, it shall be provided in sufficient quantity at the beginning of the work shift to provide one quart per employee per hour for drinking for the entire shift.
The is (in my opinion intentionally) vague; it is to be determined by "facts on the ground". Strictly speaking, the fact that the water fountain is in another building is not necessarily against OSHA/California regulations (though it may be, and it certainly does raise eyebrows). The question is how frequently and easily can you access the water supply.
Note that "a drinking fountain" as such is not required; it is absolutely permissible to have a non-continuous water supply, e.g. water-cooler in an accessible location.