Natatoriums, particularly when located in cold climates, are among the most challenging building types for architects and engineers. Interior moisture levels are extremely high, with dew points ranging from 60°F to 70°F. At these levels, even natatoriums in mild climates are susceptible to moisture-related problems. Issues typically encountered in natatoriums are condensation on interior surfaces, condensation within walls and roofs, and corrosion of interior components. This column diagnoses these three issues and provides design guidance on how to avoid them.