It's essential to install and maintain plumbing systems in place. However, sometimes repairs or upgrades are needed, and often, those repairs involve waterlines that run beneath sidewalks or walkways.
In the past, this type of repair involved cutting up the cement, which could be costly and time-consuming. We’ve all seen the horror on a customer’s face when they ask, “Are you going to take out part of my sidewalk?”
Fortunately, several methods and tools are available that allow for a less intrusive way to punch waterlines under residential walkways without cutting up cement.
Boring method
One of the most popular methods is the boring method, which involves drilling a hole through the ground underneath the sidewalk or walkway. This method can be done using pneumatic boring tools or using an auger attached to a drill. A hole is drilled under the walkway, and then the water pipe can be inserted into the hole. The dirt is then tamped back into place once the waterline is in place.
This method is efficient, and the disruption to the sidewalk is minimal.
Push-pipe
The push-pipe method is a caveman way for replacing or repairing waterlines without excavation. This method uses a small access point that is dug on either side of the walkway. A piece of black iron pipe with a coupling, bushing and ground-down sharp tip is pushed under the sidewalk with an excavator. The black iron bushing makes for a larger face pushing through the dirt, so when you remove the bushing, you can pull the pipe right back out of the new hole and then insert the waterline.
This method can help to maintain the integrity of sidewalks and walkways, and it is an efficient alternative to traditional digging.
Hydroexcavation method
The hydroexcavation method is another way to replace pipes under walkways. It uses vacuum to extract soil, rocks, and debris from the ground while simultaneously using high-pressure water to dig a hole in the ground.
This excavation method is not only less destructive than traditional digging, but it is also safer and more efficient. With this method, the walkway remains undisturbed, and the replacement line can be inserted without cutting the cement. As long as you can get close enough with the vac truck, you can dig vertically down on both sides of the walkway, and then wand horizontally until you get enough diameter sucked out.
This method should only be used if you either have your own hydrovac equipment or have a very expensive/important walkway that absolutely cannot be disturbed because the cost of subbing out a hydrovac can be very expensive.
Directional drilling method
The directional drilling method is an effective technique that can be used to install waterlines underneath walkways without causing damage to the concrete. It involves drilling a small borehole above where the waterline will be placed and another one where the line will connect. A rod is then inserted into the borehole, which is then pulled back, effectively creating a path for the waterline. The new waterline is inserted into the path, and the borehole is then sealed up.
This method is ideal for long-distance underground installations, and it offers a solution for areas where traditional excavation methods would be too disruptive or too costly. Directional drilling is awesome, but for just going across a sidewalk it can be way overkill. It is a great option however if you need to go underneath a long section of hardscape. There are also “line pullers” now that use the same technology as pipe bursting that provide a very similar method.
Mole method
This is my favorite. Get a tow-behind air compressor, some hose and a mole. Shoot the mole under the sidewalk. The mole is a long, pointed stainless steel bullet that pounds under the ground without causing significant damage to the surrounding area. This method is ideal for smaller underground repairs or installations, and it eliminates the need for conventional methods that would require cutting into the sidewalk or walkway.
One special note with using a mole is not to use too big of a mole too shallow. The combination of too large of a diameter of mole and running it shallow under a sidewalk (or even worse a paver walkway) will result in the sidewalk or paver walkway buckling up and/or cracking. This is because the compressed dirt is pushing and must go somewhere. The easiest place it can go is up.
Plentiful options
With these techniques, contractors no longer need to worry about the high cost and disruption that comes with traditional digging and excavation methods. Instead, they can choose a cost-effective, time-saving, and less intrusive method depending on their specific needs. This not only helps to save time and money, but it also helps to reduce the environmental impact associated with traditional excavation. As technology continues to evolve and more advanced drilling tools are developed, we can expect to see even more innovative ways to repair and maintain waterlines in the future.
About the Author
Anthony Pacilla is a registered master plumber for McVehil Plumbing in Washington, Pennsylvania. He has over two decades of experience in the plumbing and HVAC trades and has a bachelor’s in business and economics from Thiel College.
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