Lantmäteriet is the agency responsible for forming community associations.
A community association can be formed to manage joint facilities such as roads, garages, and water and sewage facilities. You can find data on community associations in the Community Association Register (SFR) maintained by Lantmäteriet.

Every member pays a contribution and usually an annual membership fee. The association itself decides how large the contribution should be. Members are not personally liable for the association’s debts and other commitments in excess of their contribution. However, those who are members of the board can be held personally liable if they mismanage their assignment.

Community association at Lantmäteriet (in Swedish)