Which component helps to prevent scum from exiting the septic tank?

The outlet baffle serves an essential purpose in a septic system by preventing scum from exiting the septic tank. Scum is the layer of floating materials, largely comprised of grease and oils, that can accumulate at the top of the septic tank. The outlet baffle is specifically designed to extend below the water surface level, ensuring that only the clarified liquid effluent (the liquid component that has been filtered and is relatively free of solids) can flow out of the tank towards the drain field.

This design is crucial because it helps to maintain the integrity of the septic system by promoting proper treatment of wastewater. If scum were to escape into the drain field, it could lead to clogs and system malfunctions, potentially polluting the surrounding environment and compromising public health.

The other components, while important for the functionality of the septic system, do not serve the same purpose. The inlet baffle helps prevent solids from entering the inlet pipe, but does not address scum. The drain field is where the treated effluent is distributed for final filtration through the soil, and the distribution box is important for evenly distributing effluent to different sections of the drain field but does not play a role in preventing scum from exiting the tank.