A novel optical sensor has been designed and developed to measure light through water samples for the retrieval of total suspended solids (TSS) concentrations. Light-emitting diodes (LED) were used as light sources of this sensor. In case 1, light was transmitted through the sample when the angle between light source and photodiode was 180°, and for case 2, light was scattered by small particles in the sample when the angle between light source and photodiode was 90°. An algorithm equation was developed and used to determine the relationship between measured TSS and predicted TSS.