This study examined the distribution of authority over decisions made during investigations within child welfare services (CWS). The distribution between various actors, such as social workers, citizen representatives and managers, was examined regarding 19 key decisions that frequently occur during investigations. The study also examined how the municipal socio-economic status and the internal organizational conditions of CWS impact the overall hierarchical level of authority using linear regression analysis. The study was a full population study of Swedish municipalities and districts in larger cities (n = 309, response rate of 62%). The study indicates that the head of the unit holds authority over most decision types, followed by the social worker. However, the study also indicates that there are significant variations between municipalities and decision types. In the municipality delegating authority to the lowest hierarchical level, social workers hold authority over 15 decision types compared with two decision types in the municipality delegating authority to the highest hierarchical level. This variation concerns most decision types except two, where authority is almost exclusively delegated to the same actor in all municipalities. The regression analysis indicated that the educational level of the municipal inhabitants and the size of the CWS budget were the strongest predictors of the hierarchical level of authority in a municipality. High educational levels in municipalities are associated with delegating authority to low hierarchical levels, such as social workers, whereas large CWS budgets (spending as SEK per inhabitant) are associated with delegating authority to high hierarchical levels, such as top-level managers. The implications of these results for social work research and practice are discussed.