Compositions and methods utilizing Raman Spectroscopy to detect and determine, directly or indirectly, the concentration of water treatment polymers in water or methods for measuring or quantifying the amount of water treatment polymer in a sample, such as an industrial, commercial, or municipal water sample, are provided. The compositions contain water treatment polymers that have been modified to include one or more Raman-active functional groups. The methods utilize Raman spectroscopy to detect the presence or amount of water treatment polymer either directly or indirectly. The method provides the ability to detect or measure the amount of active water treatment polymer remaining in the sample.