In recent years, water scarcity in northern Chile has increased markedly, leading to an over exploitation of groundwater aquifers. In the construction sector, water is used in large quantities throughout the different activities of the construction projects, this fact makes essential to quantify the water consumption in order to know the real demand for water, and thus to have a clear and precise vision about the volumes of this resource which are used in the different activities of a construction project. In this study, the water consumption coefficients in relation to the different items corresponding to the construction of 219 homes and 2 multipurpose rooms were determined. For this purpose, the theoretical results of water demand obtained by means of calculations of the project, were compared with the results obtained in the real consumption of water in-situ. Results obtained for theoretical and real consumption of the tasks showed that the theoretical water volume to be used in the work was 10,946 m(3), this value differs with the real volume of 16,283 m(3) of water used in the project, i.e., it was used an additional volume of 5,337 m(3). The latter implies an increase of 48.8 % in water consumption, if compared to the theoretical water volume. The main water consuming activities were the following: soil compaction, irrigation to control particles in suspension, curing of concretes and mortars, worker camp, manufacture of concrete and mortars. Within these activities, the one that presented a higher than expected consumption was the irrigation for the control of suspended particles, whose theoretical value was 3,936,000 m(3) and the real consumption was 6,010,000 m(3), that is 53% higher than the provided. Considering the results obtained in this study, it is possible to estimate that in the construction sector there is higher water consumption, in comparison with the theoretical demand. In this sense, it is necessary to develop detailed studies based in the actual water consumption that guarantee the sustainability of this resource in arid zones.