Nonvolatile neutral organic compounds in tap water were examined by high-pressure liquid chromatography, infrared spectrometry, 1H- and 13C-FT-NMR, gel permeation chromatography, elementary analysis, and field desorption mass spectrometry. Neutral organic compounds in 10 m 3 of tap water were continuously extracted by the Amberlite XAD-2 resin column, and separated into four fractions by silica-gel column chromatography. Removal of volatile compounds in fraction 3 including polar oxygenated compounds was carried out with microdistillation column under high vacuum by using a diffusion pump. Nonvolatile organic compounds isolated from tap water were identified as poly(vinyl acetate) derivatives with molecular weights ranging from 300 to 1300.