Get matched with top excavation pros in Cottondale, AL

How deep your septic system needs to be into the ground depends on several factors. In extremely cold environments, the tank needs to rest below the maximum frost line, which can be up to six or eight feet deep. The standard burying depth for most systems is between a few inches and four feet below ground level. Depth can also depend on the slope of the landscaping and other property variables. 

Sewer lines can be buried anywhere from 18 inches to 8 feet deep, with a common average depth between 18 and 30 inches. The exact depth depends on local factors like climate and soil type. In colder regions, pipes must be buried deeper (below the frost line) to prevent freezing, sometimes as deep as 8 feet. The digging depth can also impact the cost of sewer line replacement. To find the specific depth for your property, you can check the building plans for your system, which should be on file with your city or local sanitation department since permits are required for installation.

A trench that is less than 5 feet deep often doesn't require a protective system. Most residential trenches will not go this deep (the typical residential drainage trench is just 18 inches deep). In the event that an excavator needs to dig more than 5 feet beneath the surface, a protective system is required unless the excavation is in entirely stable rock.

The average cost of excavation is approximately $3,200, with typical projects ranging from $500 to $15,000. Depending on the contractor, you may be charged between $50 and $200 per cubic yard or an hourly rate of $40 to $180 for an excavation specialist. The total cost is influenced by several factors, including the project size, the amount of soil to be removed, and the soil's condition. Hard soil, tree roots, or excessive rocks and clay can increase the price, potentially adding $200 to $1,200 to the final bill. Other factors that can drive up costs include the presence of nearby structures that complicate the work or tight spaces that require manual excavation instead of heavy machinery.