The topic of this master thesis is the "Siedlung am Wasserturm" (a housing estate near the water reservoir tower), which is located in the 10th district of Vienna. The housing estate was designed by the architects Franz Schuster and Franz Schacherl in 1923, it consists of 190 row houses and is located in a so called "protection zone". It is the first housing estate of "Red Vienna" which was sold to its residents. The "Siedlung am Wasserturm" is rich in detail and consists of different groups of row houses with optimized room layouts and simply decorated facades. Due to individual alterations, the former uniform appearance of the "Siedlung" is about to be lost. It is the aim of this thesis to further protect the unique character of the housing estate and to achieve that the historical structure of the "Siedlung am Wasserturm" is valued and treated carefully in the future. Therefore, the development of the "Siedlung", as well as the architects-plan and its different types of houses are analysed in the first chapters from a historical viewpoint. In the main section, the characteristics of the historical appearance and its changes are shown. Based on these results, recommendations are given, how to protect and treat the "Siedlung" in the future, in order to prevent that alterations destroy the ensemble.