How to dig an irrigation trench, and not cut pipes, phone wires, your cable TV etc

Shorty Misc Projects >> Article By Shorty


So here is the problem, one of my sprinkler irrigation pipes broke underneath my back porch, and I needed to re-route it around the porch, and splice in with another pipe which I didn't know exactly where it was. I am pretty good and quick with a pick axe, but there doesn't seem to be a gentle way to dig a trench without busting thru whatever is underground. I asked everyone if they knew a way to dig a trench without cutting into previously laid pipe and wires, but nobody had a solution except one guy said "dig with a pickaxe gently", and anther guy said that he just uses a power trenching tool and repairs whatever he cuts, or lays out new pipe & wires in the new trench and abandons the stuff he destroys.

So here is a solution I discovered one day when digging a hole. One trick I was told was to fill the hole up with water and let the dirt get moist, then it is easier to dig more. I was doing that and noticed that when the sprayer was pointing at the side of the hole, it would easily cut into the dirt. Then I started going in a line from there and came up with this method.

Here are the tools that are needed - a trenching shovel, a bottomless plastic jug, and a pressure nozzle that screws to the end of a garden hose. These are advertised to be used for cleaning off your driveway, they create a high pressure stream - costs only $2. Also the yellow thing is an inline ball valve so I can shut off the water right there and not have to walk back to the nozzle at the house.

First thing I do is dig a narrow hole that is just big enough for me to bail water out of, with my bottomless jug. Then I use the spray nozzle to cut into the dirt along the path that I want to trench.

The water flows down hill and into the hole I dug, which I can then bail the water out of.


Hey look at that - water that floats in the air. :)

After a few cycles of spraying and bailing, you end up with a thin, narrow, deep trench.

As you can see from the picture, I was able to locate the irrigation pipe without breaking it. Even the small tree roots are still intact.

The only drawbacks to this is that you displace a lot of the dirt, it gets distributed around your throwing radius. Possibly if you had a big barrel, you could put the water and dirt in there so you could seperate it and put the dirt back in your trench. I have a big pile of dirt in my back yard from digging my pond so I just get some from the pile to fill the trench back up again.

How to dig a hole and get a pipe under your
driveway or sidewalk, without breaking it

While figuring out the method above for digging tranches, some friends told me about a similar technique for drilling a hole thru the dirt under your driveway - so you don't have to cut thru the concrete and re-patch it. What you do is attach a pressure nozzle to the end of a piece of PVC pipe. Same kind of nozzle I used for the trench project. Attach garden hose to the other end, turn the water on and it acts like a big drill bit.

Makes a huge mess, but can drill a hole thru the mud so you can fish a pipe in thru there, or wires or whatever.