Described is a metering pump that may be used to meter volumes of sample in a chromatography system. The metering pump has a modular configuration that allows for separation of a head pod from a drive assembly for easy serviceability. The head pod includes a pump head, cartridge housing, seal wash housing and plunger. The drive assembly can be implemented in an inline drive configuration. Alternatively, the drive assembly can be implemented in an offset drive configuration in which a stepper motor is displaced laterally from other drive assembly components but is coupled through a belt and pulley system.