Is There a Role for Trenchless Technologies in LCR Compliance?

lead pipe
By Jonathon Meyer

The U.S. Environmental Protection Agency’s (EPA) Lead and Copper Rule (LCR) revisions that are currently under consideration are anticipated to have far-reaching implications on the capital and operating costs of cities, towns and agencies with lead service lines (LSLs). The full replacement of LSLs will be an essential element of complying with the LCR requirements and will require substantial funding. As such, the use of innovative technologies can be a key component in minimizing the per service line replacement unit cost.

In some situations, open cut replacement can be a cost-effective solution, however, in other situations trenchless technologies can be more cost-effective than open cut. For example, the Lead and Copper Rule Revisions (LCRR) do not allow for partial replacements except in emergencies, therefore the replacement must be performed starting at the water main, all the way to the inside of the home. A scenario such as this lends itself well to the use of a trenchless option.

The Issue

In conjunction with water main replacement projects, many municipalities are proactively incorporating LSL replacement into the project scope to meet the upcoming LCRR compliance requirements. As the water main is generally being replaced on a block-by-block basis, the residents, as well as public traffic, are impacted by the noise and lane closures caused by the installation of a new water main in a public right-of-way. By including LSL replacements into the project, a utility can reduce the total disturbance time on a street through this project combination approach since they do not have to return in the future to replace the LSLs. However, costumers will be impacted to a greater extent when the work needs to be performed in their yards or inside their homes. Extending the replacement into costumers’ yards increases the risk to the utility. These risks include damage to mature trees, damage to existing fences and porches, damage to adjacent sewer lines, flooded basements, damage resulting from construction activity inside the homes, as well as disturbances related to the LSLs temporarily increasing the lead concentrations in the drinking water. Impacts such as these can be minimized by utilizing trenchless options.

Trenchless Technologies

Several trenchless technologies are currently available to be used when installing new water service lines. These technologies include the following:

  • Pipe pulling
  • Horizontal boring
  • Standard horizontal directional drilling (HDD)
  • Pit launched horizontal directional drilling (from excavation pit in the right-of-way)
  • Interior launched HDD (from an excavation located inside the home)

Determining which technology to choose depends on various factors. These factors include soil conditions, space availability, location of existing utilities, availability of experienced contractors, and the level of accuracy and control required to ensure the trenchless tool does not damage an existing utility line. Pipe pulling, defined as the technique of pulling a new water service line using the same borehole as the existing LSL, is a cost-effective approach at face value. However, pipe pulling may not always be feasible. For example, pipe pulling cannot be performed in jurisdictions where the sewer and water service separation does not meet current plumbing codes, and when the replace-in-kind water service on an existing home cannot be grandfathered in. Another limitation to pipe pulling is when the soil condition is such that the existing lead line has the potential to break during the pulling operation. This situation will therefore require resorting to an open cut solution.

Horizontal boring, which uses a pneumatic piercing tool (sometimes known as the bullet or mole) is another commonly used trenchless technology. This technology, however, does not have the required high degree of control and accuracy which is needed to avoid hitting existing utility lines. When the control and accuracy of the installation are the main concerns, HDD will be a better trenchless option.

Space limitations may impact the use of HDD, but a resourceful contractor can often find a creative solution. For example, if the required set-back required for a standard HDD is not available, the contractor may install an excavation near the water main, and use pit launched HDD. Using the same pit, the contractor can rotate the machine in either direction to install services on either side of the street.

Final Thoughts

Currently there are several trenchless technologies available for LSL replacements. With the anticipated increase in the volume of work created by the LCRR and other potential replacement projects, it is anticipated that newer techniques and improved versions of existing technologies will be developed. In certain circumstances, a combination of these technologies may even be implemented.

Homeowners will likely demand better ways of doing these replacements so that the impact to their yards is minimized. Trenchless solutions will be useful options for municipalities to implement as they embark on a program to achieve LCRR compliance, while simultaneously minimizing risk. The industry will undoubtedly continue innovating and developing more cost-effective trenchless solutions that further minimize impact to the homeowner. There is no doubt that trenchless technologies can, and will, play a role in the cost-effective replacement of LSLs.

Jon Meyer, P.E., is a project manager and senior civil and environmental engineer with CDM Smith and based in Chicago, Illinois. Meyer has experience in a wide variety of design and construction management services from municipal to transportation to energy to industrial.

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