While in Costa Rica, AyA (water and wastewater government agency) requested that Global Water Stewardship inspect a facultative lagoon treatment system that is located in a community in the mountains called San Isidro. This system is one of very few centralized treatment systems in the country. It is functioning poorly and is a source of odors. It appears that it was sized for a much smaller population when designed. The influent pipe is fully submerged, even in dry weather. It is aerated through aspirators that are likely insufficient for the aeration required. AyA has provided GWS with engineering plans and data to continue evaluation and make recommendations to improve its functionality and effluent quality.