In general, the government’s provision of public infrastructure is carried out because it is part of the government’s obligation to provide public services. However, several cases show that an institution formed by the community manages the public infrastructure. One of them is the Panggung Lor Floods and Tidal Empowerment Management Association which is known as P5L (Paguyuban Pemberdayaan Penanggulangan Air Pasang Panggung Lor). The institution was created by residents of the Panggung Lor Sub-District in North Semarang District, Semarang City, Indonesia, to overcome and prevent floods and big tidal problems in the sub-district area. Since it was formed in 2000 until now, the institution has succeeded in overcoming its problems. This article examines the research results on P5L as an institution developed by the community to manage a public infrastructure that the government usually manages. Qualitative research is used to carry out the institutional analysis framework developed by Wageningen University and Research. This study indicates that since its establishment until now, P5L has been able to carry out the mandate given by residents of the Panggung Lor Sub-District and foster a sense of security against floods and high tides. The reason is that P5L can show good performance in 4 aspects, mainly that it can boost public confidence that the institution can manage the drainage system built on a community basis; However, initially, it was an independent institution formed and supported by the community currently it has become a partner of the government in managing parts of the urban drainage system; its services can create a residential environment that is free from floods and high tide and in green and clean conditions; as well as the supervision of its works is carried out directly by the community, as part of maintaining the trust given to the institution. For the institution’s existence to continue, the mandate given by the community must be upheld.