Wastewater monitoring is necessary to preserve the quality of water in publicly water bodies. In particular, the presence of colored pollutants in wastewater inhibits the photosynthesis of seaweed, and therefore requires adequate treatment for its removal.We developed a surface-enhanced Raman scattering (SERS) sensor for the detection of color-polluted water. Silver particles on a quartz substrate were grown via mist chemical vapor deposition; this substrate was built into the sensor to enhance its Ramanscattering signals. Aqueous solutions colored with a single dye were detected at concentrations as low as the ppb level, and the intensity of their SERS spectra decreased with the dye concentration. Additionally, we evaluated the performance of the SERS sensor using mixed dyes dissolved in river-water, making assumptions suited to practical occurrences results demonstrated that our sensor depicts the molecular features of each dye in the river-water sample, clearly detecting them at concentrations as low as the ppb level. Therefore, this study proved that SERS can be applied in an environmental spectroscopic sensor.