How Much Dirt Should Cover Septic Tanks?

Homeowners who are building new homes or renovating older houses outside city limits may encounter questions about septic systems, including where and how deep they should be buried in the yard.

Function

For homes that are not connected to city sewage services, septic systems offer an efficient alternative. The septic tank collects and treats household wastewater. Solids settle to the bottom of the tank and the treated water leaches into a nearby drain field.

Depth

Unlike many household projects, there are no hard and fast rules with septic tanks. In general, any depth of placement will work. Because septic systems rely on gravity, they work best when buried deeper than the sewer line feeding the tank.

Considerations

Before installing a septic tank, homeowners should consider the type of soil and the presence of bedrock. Will a sewage grinder or pump be used? To ensure grass grows over the septic tank, add a 6- to 12-inch layer of soil.

References

• Soil Facts: Septic Systems and their Maintenance
• University of Maryland: Septic Systems

Resources

• InspectAPedia: Septic Tank Design