This project was for the renovation and rehabilitation of two large concrete underground reservoirs in Washington, DC. Major work items included selective demolition, concrete repairs, site work, and utilities. There was also process mechanical, ventilation, electrical, security and surveillance work. Another major item of work was the installation of geofoam and impervious membrane liners on top of the reservoir roof for waterproofing. The project was heavily phased due to water usage restrictions by DC Water. Most of the concrete repair work for this project occurred inside the reservoirs. Working inside the reservoirs was challenging, as we were dealing with a confined space, and stringent safety measures that had to be put in place. Concrete work included cast-in-place concrete, curing, finishing, precast concrete, non-shrink grout, repairs, formwork, anchoring, waterstops, reinforcing steel, welded wire reinforcing, concrete accessories, and joints. Process mechanical included instrumentation and controls, programmable controller system (RTU) and communications panel, and uninterruptable power supply.