Metalized paper, standard wood-pulp paper coated with aluminum, is commonly used in many forms of packaging. Recently, recognition of metalized paper as a medium for innovative new applications is growing since it is an extremely affordable, conductive medium. In this project, gridded metalized paper substrates act as the separate plates of a capacitor and are used to detect water leakage. An Arduino Uno unit monitors the increase in capacitance caused by water touching the metalized plates, and thus locates water leakage. The Arduino then sends data to a computer that conveys the location of the leak to the user. Using these paper-based, water-detecting sensors, leaks can be discovered in private, public, and military spaces to avoid irreversible water damage.