Septic tank T-baffles serve a very important role within a residential wastewater system. The inlet baffle is designed to slow the flow of sewage material coming into the tank and redirect it towards the bottom. Here, the sludge does not collect towards the surface where scum has already taken hold. The outlet baffle is designed to contain solids within the septic tank and allow only effluent fluids to pass into the leach field. Outlet baffles now contain effluent filters, which trap fine particles from leaving the septic tank.