A wearable infusion device comprises a reservoir that holds a liquid medicament, an outlet port that delivers the liquid medicament to a patient, a pump that holds a volume of the liquid medicament received from the reservoir and displaces substantially all of the volume of the liquid medicament when actuated, and at least a first valve, a second valve, and a third valve. The valves establish fluid connection between the reservoir and the pump when in a first valve configuration and establish fluid connection between the pump and the outlet when in a second valve configuration. At least two of the valves isolate the outlet from the reservoir when the valves are in the first valve configuration.