The most accurate values to date were determined for conductivity of water from 0-100 degrees C, permitting new determination of high-temperature hydroxide ion equivalent conductance. These values were incorporated into a fundamental water coefficient table including hydroxide and hydrogen ion mobilities, water ionization constant, density, conductivity, and resistivity. The conductivity/resistivity values were measured with a multiple-pass, closed, recirculating flow conductivity system, with improved multiple resistance temperature device measurement, and improved analysis of temperature and impurity effects. An accurate conductivity knowledge is necessary to understand water-limiting processes and to facilitate the analysis of trace ionic impurities in water. (C) 2004 The Electrochemical Society.