A valve (4) for an infusion pump device (2) comprises a pump connection (41 ) intended to be fluidly connected to a piston pump (11,12,13), an infusion site connection (42) intended to be fluidly connected to an infusion set (31,33), and a reservoir connection (43) intended to be fluidly connected to a liquid medicament reservoir (21 ). The valve (4) can be in a first state (I), where the pump connection (41 ) is fluidly connected to the infusion site connection (42), and the reservoir connection (43) is sealingly closed, and in a second state (II), where the pump connection (41 ) is fluidly connected to the reservoir connection (43), and the infusion site connection (42) is sealingly closed. The valve (4) comprises one or more conduits, grooves, and/or recesses (441) vented to environment (46) that are arranged in such a way that no path can exist within the valve between the infusion site connection (42) and the reservoir connection (43) that would not cross at least one of said conduits, grooves, and/or recesses (441 ), thereby establishing a drain, in case that one of the sealings of the connections would leak. In this way, leakage between the reservoir and infusion site connection is prevented in case of valve malfunction.
