Septic Tank Baffle Information

In homes that are not connected to public sewer systems, septic systems are often used to treat wastewater. Septic systems remove harmful pollutants before returning wastewater, or "effluent," to the environment. Typical underground septic systems include both a septic tank and a leach field. The baffles are located inside the septic tank.

What are Baffles?

Baffles are thin mechanisms that are placed inside a septic tank over both the inlet and the outlet. Their general purpose is to direct the flow of wastewater. Baffles help to determine where wastewater goes within the septic tank. Baffles also help to keep wastewater within the septic tank, which has a number of positive effects for the septic system as a whole.

History

Baffles were added to the design of septic tanks in 1905. Initially, they were made of oak. Later baffles were composed of concrete, because concrete baffles lasted longer. Today, septic tank baffles are made of PVC plastics, because plastic lasts even longer than concrete and is less susceptible to weathering.

Inlet Baffle

One baffle is placed just inside the inlet of a septic tank, where wastewater flows into the tank from the home. This baffle slows down sewage as it enters the tank, which helps solids separate from liquids. The inlet baffle also contains a vent that allows gases to escape the tank, which helps to ensure that effluent travels smoothly through the system.

Outlet Baffle

A second baffle is placed inside the septic tank at the outlet. The purpose of this baffle is to prevent scum from exiting the tank and going into the leach field. By ensuring that scum and solids remain inside the tank, the outlet baffle helps to keep the leach field pipes free of clogs. This minimizes the risk that the septic system will back up, flood or otherwise fail.

Warnings

Although baffles made of PVC last for a long time, they should be inspected periodically to ensure that they are functioning properly and have not fallen off. Older baffles that are made of concrete should be inspected for holes or cracks. When a septic system is pumped, it should be through the larger manhole opening on the top and never through either the inlet or outlet, as this can damage the baffles.

References

• University of Maryland: Septic Systems and Their Maintenance
• Roman Septic: Septic Information
• Purdue University: Operating and Maintaining the Home Septic System
• University of Georgia: Septic Tank Design and Construction