During the process of compressing air, atmospheric air along with water vapor and airborne contaminants are ingested into the air compressor. Many of these compressors utilize oil for lubrication, sealing and cooling. A compressor system utilizes drain valves to remove the condensate that accumulates in the system which are typically located on the compressor, moisture separators, coalescing filters, receivers, dryers, and drip legs. While the drain valves successfully remove the condensate, this condensate is now contaminated with lubricant. The compressor system also includes a filter for the removal of lubricant from the condensed water so that the water can be discharged to sewer. The filter is arranged to house a series of vertically stacked filter cartridges, each cartridge structured to pass fluid flow to the other cartridge. The housing is connected to the filter cartridges via a variable length pipe extension dependent on the number of filter cartridges used in an application.