30 CFR § 57.20002
Potable water.
(a) An adequate supply of potable drinking water shall be provided at
all active working areas.
(b) The common drinking cup and containers from which drinking water
must be dipped or poured are prohibited.
(c) Where single service cups are supplied, a sanitary container for
unused cups and a receptacle for used cups shall be provided.
(d) When water is cooled by ice, the ice shall either be of potable
water or shall not come in contact with the water.
(e) Potable water outlets shall be posted.
(f) Potable water systems shall be constructed to prevent backflow or
backsiphonage of non-potable water.