Abstract: The invention concerns a portable solar-thermal device (1) for the production of fresh water from sewage water or salt water. The device is characterised in that it has a closed fluid circuit (2) made of connected pipe or hose elements with a sewage water supply (3) and a fresh water runoff (4) with the fluid circuit (2) having a tilted heating section (5) essentially aligned normally to the sun irradiation (S) for heating and vaporisation of the sewage water. Connected to this is an essentially vertically aligned condensation section (6) for condensation of the fresh water and heating of the sewage water, and a storage section (7) designed as base area for the condensed fresh water. The heating section (5) of the fluid circuit (2) is characterised by a solar collector (10) for concentration of the thermal energy of sun irradiation (S) on a vaporisation area inside the heating section (5).