The volume of water consumed by the parliamentary estate in each year since 2004 is as follows:
Mains water Borehole water Total 2004-05 216,861 301,842 518,703 2005-06 186,663 393,859 580,522 2006-071 139,477 258,149 397,626 1 Nine months.
Borehole water is used primarily for cooling and toilet flushing in Portcullis House.