The water and subsurface sector faces numerous urgent challenges related to climate adaptation and sustainable infrastructure. It is the responsibility of Rijkswaterstaat (RWS) to establish objectives and collaborate with partners in the sector to address these challenges. Innovations are crucial for effectively addressing these issues, and therefore, RWS has developed an innovation strategy focused on the tactical level, which provides essential information for its employees and partners. This study examines RWS’s current innovation strategy and its development, evaluates the strategy’s influence on innovation processes within the water and subsurface sector, and offers recommendations for enhancing the strategy. Specifically, the study investigates the influence of RWS’s innovation strategy on resource allocation, the development and diffusion of innovations, and both internal and external collaboration. The findings indicate that the influence of RWS’s innovation strategy is most evident in resource allocation, where its focal points serve as guiding principles for innovation and as accountability mechanisms. Furthermore, the influence of the strategy on the development and diffusion of innovations, as well as on both internal and external collaboration, is becoming increasingly apparent in practice; however, it requires additional time for further visibility. Positive developments include the adoption of specific tools designed to stimulate the innovation process and the implementation of innovative collaborative approaches, such as learning spaces. To enhance RWS’s innovation strategy and its influence in the water and subsurface sector, this study recommends maintaining continuity, improving visibility and clarity, and stimulating sector-wide collaboration and alignment.