Attach a threaded hose adapter to the length of metal or PVC pipe you want to install under the driveway. These are commonly available at most home and garden centers and will vary depending on the size of the pipe and hose being used.
Attach a garden hose to the excavation pipe's hose adapter.
Dig a small trench on each side of the sidewalk, where the pipe will be inserted and where it will emerge on the opposite side. Don work gloves and safety goggles and turn on the water.
Push the pipe under the driveway and move it in a back and forth motion using the pressure of the water to displace the soil. Continue until water is observed emerging from the trench on the opposite side.
Wait for excess water and mud to settle and insert the pipe into the tunnel created by the water.
Select a metal pipe of sufficient diameter for the desired excavation width. A one-inch metal or PVC pipe digs a hole suitable for most projects.
Choose a sledgehammer heavy enough to drive the pipe through the soil.
Excavate a small trench of sufficient width and length to insert the end of the pipe slightly under the driveway and another on the opposite side where the pipe will emerge.
Secure the pipe in the desired position and drive it under the sidewalk with a series of sharp blows to the exposed end.
Remove the pipe periodically to shake out excess dirt and observe the pipe's progress. Continue driving the pipe under the sidewalk with hammer blows until the buried end emerges on the other side.
Insert the conduit into the tunnel bored by the pipe.