Water tanks, including stainless steel water tanks; water purification and filtration units, including multiple cartridge filtration systems, sediment removal systems and chemical removal systems, all the foregoing not being for effluent, sewage and waste water treatment; water heating units; water chilling units; combination boiling/chilled water filtration units; combination boiling/hot/chilled water dispensers; dispensers for delivering either boiling, hot or chilled water; parts and accessories therefor such as are in this class