Volatile suspended solids (VSS) is an analytical parameter representing, loosely, the undissolved organic matter in a water sample. More technically, it is a water quality parameter obtained from the loss on ignition of total suspended solids.[1] This ignition generally takes place in an oven at a temperature of 550 °C to 600 °C. It represents the amount of volatile matter present in the undissolved solid fraction of the measured solution.