A water processing system (10) comprises a reactor (12) configured to receive a feed water input (FW). The reactor (12) is configured to convert the feed water input (FW) into a steam output (S) for use in a downstream operation. The processing system (10) is configured to utilise the thermal and/or mechanical energy of the feed water input (FW) to partially power the conversion of the feed water input (FW) to the steam output (S). The system (10) further comprises a heat generator arrangement operatively associated with the reactor (12), the heat generator arrangement supplying the remaining thermal energy required to convert the feed water input (FW) into the steam output (S).