A priority in Environmental Control and Life Support systems for extended space missions is to recover and process wastewater to provide potable water for crew consumption and oxygen generation. Total organic carbon (TOC) indicates the overall quality of reclaimed and stored water and their suitability for crew consumption by indicating the potential presence of hazardous chemicals. For extended missions, water monitoring requires reliable, real-time, online sensors, with limited or no need for resupplied chemicals, and low equivalent system mass (ESM). The goal of this project is to develop a reliable, compact, flight-qualifiable, microgravity-compatible, TOC analyzer (TOCA) for online, real-time water monitoring with an operational lifetime of 5 years with no need to resupply chemicals or water. Key components include an electrochemical unit that eliminates the need to resupply or store chemicals, an effective oxidation processor for TOC conversion to carbon dioxide, a compact, stable inorganic carbon sensing unit, and mesofluidic design for reduced ESM. During Phase I, Lynntech successfully demonstrated the feasibility of the proposed system by designing, fabricating, and testing both the critical components and an integrated breadboard TOCA. During Phase II, an optimized, reliable, compact, flight-qualifiable, microgravity-compatible TOCA prototype will be designed, fabricated, tested, and delivered to NASA.