The smart waste management system implemented in the municipality of Cascais combines the use of underground waste containers with a technology of remote fill-level sensors. While underground waste containers reduce visual impacts and maximize the use of urban space, remote fill-level sensors installed in these containers enable to trigger and manage a smart collection when these are nearly full. The sensors read the level of waste in each bin and transmit the data to a central management platform, which then allows to determine when and how the collection vehicles should start their route. This management platform can be accessed remotely in any web browser. Installing underground waste containers and equipping them with remote fill-level sensors resulted in cost reductions for municipal waste services of Cascais, while simultaneouly improving the services.