This is what sets mineral water apart from spring water by law: – Mineral water must come from an officially recognised underground water source, whereas spring water can be from any underground source. – Mineral water’s chemical and mineral composition must be stable over time and its original purity must be preserved, whereas spring water composition does not have to be stable over time. – Mineral water can only be subject to very limited treatment and cannot be chemically treated under any circumstances. – Mineral water must be bottled at source, whereas spring waters come from a natural source but are bottled off-site, processed and purified. – Mineral water will state the named source on the bottle. – It is a requirement to label natural mineral water with a statement of analytical composition, indicating the characteristic constituents of the water, whereas there is no requirement for spring waters to display this statement. – Mineral water sources undergo two-years of microbiological testing. More information available from the Gov.uk website.