Two chemical isolation methods, closed-loop stripping analysis (CLSA) and simultaneous distillation/extraction (SDE) in combination with gas chromatography/mass spectroscopy (GC/MS) and two sensory methods, flavor profile analysis (FPA) and sensory GC analysis, were used to determine the compounds responsible for the fishy/swampy odors in potable water. Samples were collected during four different fishy/swampy odor episodes and analyzed. It was determined that the compounds should be extracted by the SDE method. The SDE method extracts more polar compounds than the CLSA method. The main compounds identified were two unsaturated aldehydes (trans,trans-2-4-heptadienal and trans,4-heptenal). A ketone (1-penten-3-one) was tentatively identified.