How to Tunnel Under a Sidewalk or Driveway

I recently ran a new driveway lighting system along my driveway. To my disbelief, I found out that the sidewalk prevented me from hiding my wires underground. I couldn’t go over the sidewalk with the wire and I definitely wasn’t going to cut a groove into the sidewalk just for a wire. I had no choice but to go underneath it. I wanted to make a small tunnel so I didn’t want to dig underneath with a small trench shovel. I figured that a large tunnel underneath the sidewalk might destroy its structural integrity.

I remembered once along time ago when I was doing a room addition for a couple, we had to install a new water line through the footer and into a small crawl space. The plumber who was working the job came up with a simple plan that worked well.

First, we dug a trench perpendicular to the wall and footer in the slab. We then drilled a hole through the footer with a large concrete drill bit and chiseled enough out to place a pipe through. Then he took a scrap piece of pipe, cut a 45-degree end on the PVC pipe, and drilled a hole at the other end. He inserted a small piece of rebar scrap he had in his truck, into the hole to use as a handle for his homemade auger. He turned the PVC pipe around until it would go no further, then he pulled it out, tapped the dirt out and continued along in this fashion until he had a nice clean hole that led into the small crawl space. It worked perfect and it only took him about a half an hour the auger the hole into the crawl space.

I used a similar technique when going under my sidewalk. After I dug a trench on both sides of the sidewalk, I inserted the PVC pipe into the ground. After about two feet underneath the sidewalk, I ran into some problems. The soil was very hard and compacted. It was difficult to get the pipe to turn so I had a great idea. I got out my pressure washer and stuck the tip into the pipe. The high pressure of the water blasted back out of the PVC pipe along with the hard soil. I turned the pipe and blasted the dirt and rocks loose from the underneath the sidewalk. In a few minutes, I had the pipe underneath the sidewalk. I left the PVC pipe underneath the sidewalk and ran my wires through the pipe. This kept the ground stable underneath the sidewalk, and it made it easy to slide the wires through. Later I decided to extend my lighting system and made an attempt at going under the driveway using the same technique and it worked perfectly. I used a longer piece of PVC and the pressure washer as before to the same degree of success. I did have to turn the pipe a lot more because of the length of PVC but with a little hard work I prevailed.

I’m sure you could do the same type of thing with a garden hose and enough pressure as long as the soils not to hard and rocky. Make sure you don’t get the hose stuck in the ground, and the water pressure is high enough. Turn the PVC and don’t forget to cut a 45-degree angle on the pipe.