The Food Safety (Fishery Products and Live Shellfish) (Hygiene) Regulations 1998

7.  facilities to provide adequate supplies of potable water, or alternatively of clean seawater or seawater treated by an appropriate system, under pressure and in sufficient quantity. However, by way of exception, a supply of non-potable water is permissible for the production of steam, fire-fighting and the cooling of refrigeration equipment, provided that the pipes installed for the purpose preclude the use of such water for other purposes and present no risk of contamination of the products. Non-potable water pipes must be clearly distinguishable from those used for potable water or clean seawater;