A solenoid pump that includes a base and a solenoid having a coil and a pole piece. A retainer body, positioned inside the solenoid and the base, includes an armature cavity that receives an armature in a sliding fit for movement between energized and de-energized positions. A diaphragm, mounted in the armature cavity, is connected to the armature. An inlet check valve permits fluid flow in only a first direction moving from an inlet port toward the diaphragm. An outlet check valve permits fluid flow in only a second direction moving from the diaphragm toward an outlet port. A fluid flow path extends through the retainer body from the inlet check valve to the diaphragm and from the diaphragm to the outlet check valve for transporting fluid from the inlet check valve to the outlet check valve as the diaphragm oscillates between first and second positions.