Abstract: Apparatus for use in distilling water, comprising a heating arrangement (20) for heating incoming water and thereby producing steam, a condensing arrangement (26) in a flow path of the steam from the heating arrangement (20) for producing condensed water from the steam, the arrangement being such that thermal energy from the condensing steam can be employed to heat the incoming water in the heating arrangement (20). The apparatus further comprises a pre-heating arrangement (16) upstream of the heating arrangement (20) in the flow path of the incoming water and in the flow path of the condensed water from the condensing arrangement (26) for transferring thermal energy from the condensed water to the incoming water.