Prior to excavation, you should prepare the dig site and call 311 before you sign anything.

To get your site ready for excavation, you should move anything in the area that isn’t affixed to the land. You can save money on the excavation by removing hardscaping, including walkways, decks, concrete patios, and paver patios.

Before you carry out any digging, you should call 311 to confirm that there are no utility lines running through your excavation site. Skipping this step could lead to severe injury and property damage if your excavator hits a water, sewage, or gas line.

A mini excavator can dig between 5 and 11 feet deep, depending on the type and size of the mini excavator. Mini hydraulic excavators are more powerful and can reach deeper into the earth, but electric models have a more limited range. Mini excavators over two tons in size are also more powerful and able to dig as deep as 11 feet.

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.

Trenches are typically 12 to 24 inches deep and 8 inches wide. However, the required depth depends on the specific project and local ordinances. For example, a French drain may need to be 18 inches deep, while a water pipe might require a depth of 24 inches and a drainage pipe 36 inches. Your city or county may have specific regulations, so it's wise to consult with an excavation professional to determine the correct depth for your project.