Living walls (LW) are innovative Urban Greening systems that represent a promising tool for sustainable construction and bioclimatic design. LW use a growing media to support plant establishment and growth in a vertical plane. A drip irrigation system is mandatory to be installed to supply water and nutrients to plants. As the number of LW installed in urban areas is rapidly growing, it is important to conduct studies to optimize irrigation water use. This work has therefore two main objectives: (i) optimizing irrigation scheduling in a non-recirculating outdoor LW installed near Seville (SE Spain), and (ii) assessing LW daily water needs over the summer period. The experimental setup consisted of two 2x1 m multilayer LW modules with a plant density of 36 plants m(-2). Each module consisted of two geotextile layers sewn together and forming 15x15 cm pockets, and a waterproof layer facing the wall. The system is attached to the wall by means of a metal profile. The drip irrigation system consisted of a PE drip line placed in the upper part of the LW with drippers spaced 15 cm. Water losses by drainage (i.e. runoff) were collected with a semi-circular gutter placed at the bottom of each LW module. Both water applied and water lost by drainage were recorded for each irrigation event with a volumetric water meter and rain gauge, respectively. The main microclimatic variables (solar radiation, air temperature and relative humidity) were also recorded. The runoff hydrographs obtained for three different emitter discharge rates (2, 4 and 8 I/h), as well as the estimated LW water requirements are presented and discussed. The results indicate that, for lost solution systems, pulse drip irrigation is more suitable than applying irrigation times that maximize water distribution. Living Wall evapotranspiration was highly correlated with reference evaportranspiration, which allowed to derive a mean garden coefficient of 0.75.