A wearable infusion pump system, comprising: a disposable and non-reusable pump device including a drive system to dispense medicine from the pump device, the pump device having a first electrical connector that is externally accessible; a reusable controller device removably attachable to the disposable and non-reusable pump device, the controller device including a second electrical connector that is engageable with the first connector to provide electrical communication between control circuitry of the controller device and the drive system of the pump device; and a water-resistant seal device arranged proximate to the first and second electrical connectors wherein, when the controller device is attached to the pump device, the water-resistant seal device resists migration of external contaminants toward the first and second electrical connectors (118, 218), wherein, when the controller device is attached to the pump device, the water-resistant seal device is compressed between the adjacent surfaces of the pump device and the controller device, characterised in that, when the controller device is attached to the pump device: the first and second electrical connectors (118, 218) engage one another by a guided motion in a longitudinal direction, and wherein the water-resistant seal device comprises: a polymer foam gasket coupled to an external surface of the non-reusable pump device, wherein the polymer foam gasket surrounds an electrical interface between the first and second electrical connectors (118, 218), and a major seal surface that extends generally perpendicular to the longitudinal direction, wherein the water-resistant seal device is compressed between the adjacent surfaces of the pump device and the controller device when the first and second electrical connectors (118, 218) engage one another by the guided motion in the longitudinal direction. a disposable and non-reusable pump device including a drive system to dispense medicine from the pump device, the pump device having a first electrical connector that is externally accessible; a reusable controller device removably attachable to the disposable and non-reusable pump device, the controller device including a second electrical connector that is engageable with the first connector to provide electrical communication between control circuitry of the controller device and the drive system of the pump device; and a water-resistant seal device arranged proximate to the first and second electrical connectors wherein, when the controller device is attached to the pump device, the water-resistant seal device resists migration of external contaminants toward the first and second electrical connectors (118, 218), wherein, when the controller device is attached to the pump device, the water-resistant seal device is compressed between the adjacent surfaces of the pump device and the controller device, characterised in that, when the controller device is attached to the pump device: the first and second electrical connectors (118, 218) engage one another by a guided motion in a longitudinal direction, and wherein the water-resistant seal device comprises: a polymer foam gasket coupled to an external surface of the non-reusable pump device, wherein the polymer foam gasket surrounds an electrical interface between the first and second electrical connectors (118, 218), and a major seal surface that extends generally perpendicular to the longitudinal direction, wherein the water-resistant seal device is compressed between the adjacent surfaces of the pump device and the controller device when the first and second electrical connectors (118, 218) engage one another by the guided motion in the longitudinal direction. the first and second electrical connectors (118, 218) engage one another by a guided motion in a longitudinal direction, and wherein the water-resistant seal device comprises: a polymer foam gasket coupled to an external surface of the non-reusable pump device, wherein the polymer foam gasket surrounds an electrical interface between the first and second electrical connectors (118, 218), and a major seal surface that extends generally perpendicular to the longitudinal direction, a polymer foam gasket coupled to an external surface of the non-reusable pump device, wherein the polymer foam gasket surrounds an electrical interface between the first and second electrical connectors (118, 218), and a major seal surface that extends generally perpendicular to the longitudinal direction, wherein the water-resistant seal device is compressed between the adjacent surfaces of the pump device and the controller device when the first and second electrical connectors (118, 218) engage one another by the guided motion in the longitudinal direction.