Ahmad Habibian, Ph.D., P.E.

Habibian


The adverse health impacts of lead in drinking water has been well understood for over three decades. While infants and pregnant women are at the highest risk of being impacted by elevated level of lead in drinking water, others with kidney problems and high blood pressure can also be affected.


Lead service lines are a major source of lead in drinking water. Although the U.S Environmental Protection Agency’s (US EPA) 1991 Lead and Copper Rule (LCR) has provisions for partial replacement of lead service lines under certain conditions, the problem continues to persist.


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The recent lead crisis in Flint, Michigan, has once again brought the issue to the top of the agenda, and has triggered calls for a coordinated effort to replace an estimated 6 to 10 million lead service lines in the United States. In a 2016 report, the National Drinking Water Advisory Committee (NDWAC) recommended that the LCR be revised to encourage a collaborative approach to removing all lead service lines. The American Water Works Association (AWWA) endorsed the recommendations of NDWAC.


While the US EPA has delayed revisions to the LCR, several state and local programs have still been initiated in order to accelerate the full removal of lead service lines. For example, the State of Washington has initiated a program to remove all lead service lines by 2031. Similarly, the Massachusetts Water Authority (MWRA) allocated $100 million of no-interest loans to its member water communities toward lead service line replacement. Additionally, the City of Newark, New Jersey, has embarked on a program to replace its lead service lines, and the City of Chicago is in the initial stages of establishing a lead service line replacement program.


All indications are that the Flint, Michigan-crisis has prompted action across many communities of the Country, and therefore it is expected that there will be a notable increase in the number of lead service line replacement programs nationally.


Most lead service lines targeted for replacement were installed in the 1800 or early-mid 1900s, and as such, the water distribution system serving these areas is likely in poor condition and should be considered for replacement.


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An effective method for replacing these aging water mains is pipe bursting. However, one drawback of this technique is that all service lines must be exposed and disconnected before the existing water main can be burst, and then the connection must be remade after the new pipe is pulled in place. This limitation not only increases the cost, but it also reduces the primary advantage of trenchless methods, namely minimal surface disruption. Implementing a lead service line program provides an opportunity to overcome this limitation.


When replacing lead service lines in a residential street, these service lines must be exposed and disconnected. The water main serving these residents will now be primed and ready for pipe bursting, and there will be no additional costs to dig and disconnect the service lines to perform pipe bursting. The surface disruption has already occurred and therefore would not be counted as a negative against pipe bursting. Taking advantage of this opportunity increases the cost efficiency of pipe bursting and neutralizes the surface disturbance disadvantage.


An alternative to pipe bursting is cured-in-place-pipe (CIPP) lining. While CIPP lining of water lines has been around for several years and is a primary trenchless rehabilitation method in Canada, it has not gained as much traction in the United States. The integrity of the service line connection to the CIPP liner is one of the concerns cited by some US water utilities in hesitating to fully embrace this technology. This hesitation can be overcome if the CIPP lining is performed in concert with a lead service line replacement. Having external access at the point of service line connection provides the opportunity to engineer a solution that ensures the integrity of the service line connection to the CIPP liner.


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Water utilities embarking on lead service line replacement programs should consider augmenting such programs with a main line replacement program using pipe bursting or CIPP lining. Not only will this save capital costs, but it will also enhance the level of service to their customers by offering water quality benefits and uninterrupted water service.


Like many new ideas, the idea set forth in this column should be pilot tested and fine-tuned to become an optimal and streamlined process. Considering the estimated 6 to 10 million lead service lines in the United States, it is unlikely that the total replacement of these service line will be addressed in the short-term and may take from 10 to 20 years or longer. As such, investing in a few pilot programs will be a wise decision as it will have a long period to pay back.


While the focus of this column has been leveraging existing service line replacement programs to upgrade nearby water mains as well, the cost-efficiency opportunities to leverage existing water main replacement programs to get rid of nearby lead services lines should not be overlooked either. The main point to keep in mind is the synergy and efficiencies which can be achieved when the replacement of lead service lines and renewal of main lines are coordinated and implemented at the same time.



Ahmad Habibian, Ph.D., P.E., is the Global Technical Strategy Leader for Conveyance at CDM Smith.



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