A hydraulic power unit for a braking system of a vehicle, including a first sub-brake circuit or brake circuit and a second sub-brake circuit or brake circuit, a first supply line branching into a first line section having a first circuit separating valve situated therein, and a second line section having a first electrically controllable reservoir separating valve and/or first check valve situated therein, and a second supply line branching into a third line section having a second circuit separating valve situated therein and a fourth line section having a second electrically controllable reservoir separating valve and/or second check valve situated therein.