An efficient extraction method is needed to measure trace levels of taste and odour compounds in surface waters. This is usually accomplished by costly and involved analytical procedures. We have developed a simpler alternative, using a commercially available microextraction apparatus (SPME). With this technique we successfully monitored trace levels of some target organoleptics (unsaturated aldehydes e.g. heptadienal, nonadienal, and related compounds) which commonly cause aquatic taste and odour. We identified these compounds in culture material, and analyzed for them during the development of odourous chrysophyte blooms in two ponds. Preliminary work has also found a good recovery of some important off-flavour terpenoids (e.g. geosmin and MIB). SPME is labour and cost efficient, and therefore appealing to water treatment facilities for detection and monitoring. In addition, SPME requires only small sample volumes, and is therefore suitable for culture work.