A perc test can take anywhere from one to eight hours to complete. The total time depends on factors like the amount of excavation required, the depth and width of the holes, and whether multiple test holes are needed. For a single hole, the process of filling it with water and monitoring the drainage rate usually takes less than an hour. Professionals can often complete the entire test in a single day. While it's possible to get results the same day, some companies may take a few days to provide the official report.

Excavation is priced in cubic yards, so you’ll need to find the volume of the area in order to calculate costs. Multiply the length, width, and proposed depth of your excavation site, then convert it into yards to get the volume. Multiply this figure by the price per cubic yard.

Most homeowners can measure by hand to get a rough estimate, even if it’s tedious. You may want to pull out a tape measure or use a string to help mark the area.

The best way to protect tree roots is to avoid the roots entirely by excavating outside the root radius of the tree. For nearby projects, it’s a good idea to construct a temporary retaining wall. But that’s not always possible, depending on the project and the root system. In these cases, consider using alternative equipment like an auger to tunnel under the ground.

Remember, tree roots can damage nearby cement foundations as they grow. If a tree is close enough to interfere with large excavations, it may be better to remove the tree than risk future problems.

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.