A real-time method and analytical system for determining haloacetic acids in water which operate by: (1) extracting samples on ion-exchange absorbent medium; (2) concentrating haloacetic acids on hyper-crosslinked medium; (3) eluting the analytes from the concentration medium for injection into an HPLC system; (4) separating individual haloacetic acid in reverse-phase chromatography performed by the HPLC system; and (5) measuring optical characteristics (UV-absorbance) of haloacetic acids, to determine concentration. The entire process can be performed using a completely self-contained, in-situ mechanism that sits at a water distribution point for 24/7 testing, with automated control, monitoring, reporting, and employment of remedial measures (e.g., automated adjustment of the water treatment process).