The majority of kitchen sinks, bath tubs and bathroom basins are fitted with individual taps for hot and cold water. Wall-mounted taps are known as bib tabs, but those mounted directly onto the sink, basin or tub are called pillar taps. There are also mixer taps, which have a hot and cold valve linked to a common spout. Water regulations require that mains water and stored water cannot be mixed in a system, so a sink mixer has separate waterways to isolate mains-supplied cold drinking water from storage cylinder-supplied hot water.
