The National Flood Insurance Program (NFIP) introduced the Community Rating System (CRS) to encourage community-level flood mitigation and increase individual-level flood insurance uptake. This study analyzes what factors influence communities to participate in the CRS and conditional on participation, what factors affect the type and intensity of participation over time? I used historical data of policies-in-force, claims, CRS participation, and U.S. Census American Community Survey for all NFIP communities in 11 key states to answer these questions. The results show socio-demographic factors significantly and positively predict communities' likelihood of participating in the CRS, whilst flood risk variables of claims and policies held do not. Further, flood risk variable (claims payment received) as well as socio-demographic variable (income) positively influence the intensity of communities' participation in the CRS over time.