This Report describes the findings of an investigation into the installation, commissioning and maintenance requirements for low flush WC's in order to minimise the volume of water used in flushing. These findings were intended to prepare guidance and contractual provisions for users, designers, and installers. The work includes guidance for the design, installation and maintenance of low volume flush WC's for the UK. The guidance includes details of the various flushing mechanisms: WC's siphonically flushed (traditional UK practice), WC's flushed using valves (including flap-valve, drop-valve, interruptible flush and pressurised cistern) and dual-flush WC's.