<p>A hydration pack (10) includes a bladder (11) attached to a pump (12) via a feed tube (13) and to a bite valve mouthpiece (14) via a drinking tube (15). The bladder (11) incorporates a filter cartridge (16) which is capable of ultra-filtration and thereby effective to remove viruses as well as bacteria from water. The filter cartridge (16) is coupled to the drinking tube (15) such that any water that passes from the bladder (11) to the mouthpiece (14) must pass through the filter cartridge (16). The pump (12) is able to act both to transfer water into the bladder and also to pressurize the bladder with air.</p>
