Excess nutrients are a widespread cause of water quality degradation and adverse outcomes for people and ecosystems throughout the United States. Mitigating nutrient pollution can be a complex challenge due to the diffuse nature of sources and regulatory authorities, physical and temporal distance between sources and receptors, and the performance, availability, and social acceptability of interventions. In Cape Cod, Massachusetts, stakeholders are working within this context on a range of traditional and alternative approaches to reduce nitrogen loading to impaired estuaries. Here the nitrogen source is primarily onsite wastewater treatment systems. Enhanced septic systems and wetland restoration are two biogeochemically related approaches with potential to better denitrify effluent prior to subsurface discharge or intercept legacy pollution in groundwater, reducing nitrogen loads to sensitive water bodies. The success of either approach with respect to this objective, however, depends on design and implementation. This talk will speak to efforts among a group of multi-institutional and -sectoral partners to advance denitrifying septic system technologies and cranberry farm to wetland restoration, and monitor outcomes, in order to stem pervasive groundwater pollution.