CARE Guatemala has worked in water and sanitation in Tacaná for over 10 years. CARE has helped construct potable water systems, trained community members to manage the systems, improved sanitation in schools, and led sanitation workshops for students. Most recently, CARE was involved in the Lazos de Agua (Water Links) project, which was completed in October 2016, in the municipalities of Tacaná and Tajumulco. One of the project’s main goals was to increase access to sustainable, safe water for at least 5,000 people1. In addition to providing access to clean water, it is imperative to ensure the sustainability of improved water systems into the future. In order to monitor the functioning of the water systems, the Municipal Water and Sanitation office (OMAS) was created in Tacaná in 2012. The OMAS is responsible for the operation, management and maintenance of the water systems in both urban and rural areas of Tacaná. However, neither the OMAS nor CARE have had adequate resources to consistently monitor the water systems that have been built over the last 25 years. The purpose of this study was to evaluate the functionality and sustainability of the water systems constructed by CARE and other organizations over the past 25 years in Tacaná. [11 pages]