FBE is working with the Town of Waldoboro, Midcoast Conservancy, and project partners to create a formal guidance document for conducting Septic System Vulnerability Assessments for use by Maine coastal communities to address the threat of septic system contamination to water quality. Coastal communities across Maine often face the challenge of identifying and mitigating nonpoint source (NPS) pollution from septic systems. This source of NPS pollution can contribute to elevated levels of fecal indicator bacteria responsible for closure of shellfish flats. The goal of this guidance document will be to provide coastal communities with a clear and effective roadmap for assessing and prioritizing septic system vulnerability in the coastal zone. Septic systems can be at risk for contaminating groundwater and surface water resources because of factors from infrastructure (e.g. design, maintenance) and/or the environment (e.g. underlying soil type, sea level rise). Coastal communities are at a heightened risk for septic system contamination because of the economic threat of closures to shellfish flats. Furthermore, coastal communities are facing the additional threat of septic system inundation from sea level rise. FBE will then conduct a Septic System Vulnerability Assessment within the Medomak River watershed in the Town of Waldoboro. Through extensive restoration work and the recommendations of the 2019 Watershed-Based Management Plan, the Town has recognized the need to identify vulnerable septic systems contributing to fecal pathogen impairment in the Lower Medomak River Watershed causing closures to shellfish growing areas. The case study and the guidance document will be completed in tandem and through an iterative process to ensure the effectiveness of the guidance document before it is shared with other coastal communities.