Some embodiments of the present invention relate to a reverse osmosis (RO) system that includes a housing and a pre-filter within the housing such that feed water flows into the housing and enters the pre-filter. The reverse osmosis (RO) system further includes a membrane element within the housing such that the pre-filtered water flows from the pre-filter and enters the membrane element and permeate exits the membrane element through the housing. In some embodiments, the housing includes a first end cap at one end and a second end cap at an opposing end such that feed water flows through the first end cap into the pre-filter and pre-filtered water flows from the pre-filter into the first end cap. In addition, the pre-filtered water may flow from the first end cap to the membrane element such that permeate exits the membrane element through the first end cap in order exit the housing.