Get matched with top excavation pros in Captain Cook, HI

There is no standard depth for burying a septic tank; they are typically buried anywhere from 4 inches to 4 feet underground. The final depth depends on several factors, including the depth of your main sewer line, the height of the bedrock, soil type, local regulations, and the property's landscape. If you plan to grow grass or plants over the tank, a depth of at least 4 to 6 inches is recommended. Deeper tanks can be more difficult to locate, but a septic professional can help find it for you.

A walk-behind trencher can cut through roots as long as they’re not too thick, making a project much easier than digging with a shovel and other hand tools. Assess your terrain and the number of trees in the surrounding area to determine if a walk-behind trencher will ease the job. Digging a trench by hand is much more time-consuming and labor-intensive. 

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.

The best type of soil to build on is a mixture of sand and clay, known as loam soil. Loam soil has the best combination of these soil types to build a foundation on. The clay particles help with water retention, so it won’t erode like sandy soil might, and the sandy particles help with drainage, so you won’t see unsafe soil expansion or have an increased risk of leaks from water sitting against your foundation.