Reg 22 of the Workplace Health, Safety and Welfare Regulations 1992 state that:
1. An adequate supply of wholesome drinking water shall be provided for all persons at work in the workplace.
2. Every supply of drinking water required by paragraph (1) shall -
(a) be readily accessible at suitable places; and
(b) be conspicuously marked by an appropriate sign where necessary for reasons of health or safety.
3. Where a supply of drinking water is required by paragraph (1), there shall also be provided a sufficient number of suitable cups or other drinking vessels unless the supply of drinking water is in a jet from which persons can drink easily.