The results from this study indicate that polyacrylamide polymers used for water and wastewater treatment strongly absorb light in the 191.5–230 nm wavelength range, and the peak absorbance was mea- sured at 191.5 nm for all of the seven polymers tested in this study. The detection limits in distilled water were different for different polymers and depended on polymer type and chemistry. In addition, presence of organic and inorganic impurities in water samples im- pacted the detection limits. In distilled water samples, the detection limits were below 0.1 mg / L for all polymers at 191.5 nm. The lowest detection limit measured was 0.05 mg / L. For raw and clarified water and centrate samples collected from treatment plants, the detection limits varied between 0.07 and 1.35 mg / L depending on the poly- mer type and impurities in the sample. Choosing the right dilution range also improved the sensitivity of the method and lowered the detection limits. The in-line UV–vis spectrophotometer used in this study provided a powerful tool for accurate and sensitive measure- ment of polymer concentration. The method has strong potential for research and industrial applications where the process flow charac- teristics do not change significantly. For water and wastewater treat- ment applications, it needs to be tested at full-scale treatment plants to determine whether it can successfully be used to measure and ad- just the polymer dose under varying water quality parameters and operational conditions.