As water organizations adopt green infrastructure for stormwater management to increase sustainability, new types of professionals are needed that were not previously widespread in the industry. Ecologists and other ecologically-oriented employees are being brought into these organizations that have long been mostly oriented around an engineering knowledge system. This study examines how these two different knowledge systems interact within a water organization, outlining the differences in their underlying assumptions and orientations that can cause friction. The research used a case study approach to examine implementation of asset management within a water organization that has been building and managing green infrastructure for over thirty years. It found that integration around a common decision process can occur, but that it is a slow process filled with continuous negotiation. The research suggests that water organizations looking to establish green infrastructure programs should be more aware and intentional about discussing differences in professional knowledge systems when bringing new types of professions into an established organization.