Newark Revamps Corrosion Control Strategy for Water Service Lines

A lead service line replacement by a contract crew in Newark, New Jersey, USA. Photo by city of Newark.

The city of Newark, New Jersey, USA, is introducing a new corrosion control treatment program and working to replace lead service lines on private property after tests have repeatedly showed elevated lead levels in drinking water. In 2017, Newark first reported lead levels above 15 ppb, which is the regulatory limit set by the U.S. Environmental Protection Agency’s (EPA) (Washington, DC, USA) Lead and Copper Rule.

According to the city, the majority of Newark households are not impacted because they receive water from the Wanaque water system, where tests show the corrosion control of orthophosphate is effective.1 In addition, service lines in homes built after 1986 do not contain lead due to a U.S. federal ban on lead pipes, and in 1953, the city stopped allowing new construction projects to include lead service lines and plumbing. Moreover, larger facilities, such as office buildings, apartments, hotels, and hospitals, are unlikely to have lead service lines because ductile and cast iron, rather than lead pipes, were utilized in that type of construction.

In total, the city estimates that ~18,000 privately owned, decades-old lead service lines are affected within Newark, with the vast majority coming from the Pequannock water system and largely impacting residences. According to Newark officials, lead leaches into the water when it flows through those pipes.

The Pequannock Water Treatment Plant had previously used sodium silicate (Na2SiO3) and lime as its primary corrosion inhibitor system since the mid-1990s. The compound works by forming a thin, gel-like layer on the inside of pipes to prevent corrosion, and it also raises the water’s pH levels to make it less corrosive. While the EPA, city officials, and external consultants are still working to determine the cause of that inhibitor’s failure, they chose in May 2019 to switch the corrosion control treatment to orthophosphate,2 which is used in the cleaner Wanaque system. According to the EPA, orthophosphate bonds with lead and copper ions to form a protective coating that has a strong tendency to stay in solid form and not dissolve in water.3

The system’s monitoring period from January 1, 2019 to June 30, 2019, showed lead levels of 52 ppb with 356 samples taken.4 This is up from 48 ppb and 246 samples taken from the July 1, 2018 to December 31, 2018 monitoring period and 18 ppb from the January 1, 2018 to June 30, 2018 monitoring period, and the city cautions that a decline to acceptable levels may take some time. “When we announced important new upgrades to the Pequannock system’s corrosion control system in May, we wanted residents at that time to understand that reported lead levels could continue to rise in the short term, but that ultimately our engineers at CDM Smith [Boston, Massachusetts, USA] expect them to drop in the months ahead,” says Kareem Adeem, acting director of the Newark Department of Water and Sewer Utilities. “That is because it takes time for the orthophosphate to optimize and recoat the inner linings of lead service lines to reduce corrosion.”

The city of Newark is advising affected residents to keep city water flowing, because this helps move the new orthophosphate inhibitor through the system.

Orthophosphate has been a key component of several prominent water events and decisions in recent years. For example, during the Flint water crisis in Michigan, lead levels spiked in 2014 after the city switched its water source from Lake Huron, which was being treated with orthophosphate, to the Flint River, which was not treated. And in late 2018, the Pittsburgh Water and Sewer Authority (PWSA) (Pittsburgh, Pennsylvania, USA) opted to add orthophosphate to its system after the group’s year-long study found it to be more effective than its previous inhibitors—soda ash and lime—at reducing corrosion.5 The Pennsylvania Department of Environmental Protection (Harrisburg, Pennsylvania, USA) agreed with the study’s findings, according to PWSA.

When Newark opted earlier this year to change to orthophosphate, it began offering complementary cases of bottled water to affected residents. However, the conundrum for the city is that even though it wants its affected residents to use the bottled water, it still needs them to cycle city water through the pipes in order for the orthophosphate to eventually work. “It is important to understand that long-term distribution of bottled water has potential to impact the city’s new corrosion control treatment that was launched in May,” Newark Mayor Ras Baraka and New Jersey Governor Phil Murphy explain in a joint statement6 issued in August.

“Experts expect to see a reduction of lead levels by the end of this year after the corrosion control optimizes,” the statement continues. “As part of initial filter testing, the engineers saw positive signs that the orthophosphate is in the distribution system, and we are optimistic that the orthophosphate will eventually provide the protective coating necessary to prevent leaching from lead pipes. But to continue these trends, residents must continue to keep city water flowing through their pipes, because this is necessary to move the orthophosphate through the system and form a protective coating around the inner lining of the pipes.”

Newark officials cited washing dishes, bathing, or flushing the toilet as examples of activities by residents that could help flush orthophosphate through the system. They say the city plans to continue aggressively reaching out to residents through the media, robocalls, public notice, social media, and mailings. As of September 5, 2019, the city said it had also distributed over 38,000 water filters and over 31,000 replacement cartridges free of charge, along with making water testing and blood testing for children under six years old available upon request.

For the most ideal solution, which means replacing the lead service lines altogether, Newark announced in late August that it would receive a $120 million low-interest loan, made possible by the Essex County Improvement Authority.7 “This is the culmination of all of our efforts to create a permanent solution to eliminate the risks of lead by replacing all lead service lines in our city,” Baraka says. “We have been working tirelessly to address this issue, which is why we launched the lead service line replacement [program] in March. Since then, we have replaced more than 770 lead service lines, and we are so grateful for this additional support to help us dramatically accelerate this important work.” With the bond funding, the lead service lines will be replaced at no cost to taxpayers, according to Newark officials.

However, with roughly 18,000 lines in total ranging from large 60-in (152.4-cm) lines carrying primary feed into Newark down to 6-in (15.2-cm) lines supporting individual streets and residences, the replacement effort will take significant money and time. For example, the city estimates that replacing a lead service line to just one house takes an average of four hours.8 Thus, Newark’s current projection for total system replacement is 24 to 30 months, which makes this year’s inhibitor conversion to orthophosphate an important intermediate step.

In September, CORROSION—NACE International’s technical research journal devoted to furthering the knowledge of corrosion science and engineering— released a “Flint Phenomenon” podcast series.9 The NACE Podcasts series explores the water crisis that first unfolded in Flint, including the causes of lead release in the drinking water; how the situation was handled; and a look at similar issues affecting other communities, such as Newark. Panelists include Virginia Tech University (Blacksburg, Virginia, USA) Engineering Professor Marc Edwards, who led the team that collected the water samples in Flint; Darren Lytle, U.S. EPA (Washington, DC, USA) engineer; and John Scully, technical editor in chief of CORROSION journal and chair of the Department of Materials Science and Engineering at the University of Virginia (Charlottesville, Virginia, USA).

In the ongoing series, panelists explore the science behind the problem while evaluating the difficulty of monitoring lead in water systems; the use of corrosion inhibitors, such as orthophosphate, and water filters; and the changing standards for lead in metals and drinking water. The goal is to further the discussion of methods and strategies to best mitigate these challenges moving forward.

Source: City of Newark,


1 “Quick Facts About City's Efforts to Address Lead in Drinking Water,” City of Newark News and Updates, Sept. 5, 2019, (Oct. 1, 2019).

2 “FAQs Regarding the City of Newark's Water Filters and Efforts to Address Lead in the Water,” City of Newark News and Updates, August 13, 2019, (Oct. 1, 2019).

3 “Optimal Corrosion Control Treatment Evaluation Technical Recommendations for Primacy Agencies and Public Water Systems,” EPA, 816-B-16-003, March 2016.

4 “Despite Increases in Lead Levels in First Half of 2019, Newark Turning the Corner in its Fight Against Lead,” July 8, 2019, (Oct. 1, 2019).

5 “Pittsburgh Switches to Orthophosphate to Control Water Pipe Corrosion.” MP, Oct. 26, 2018, (Oct. 1, 2019).

6 “Joint Statement from Governor Murphy and Mayor Ras Baraka on Lead Free Water Filters in Newark,” Aug. 11, 2019, (Oct. 1, 2019).

7 “Newark Has Reached a Turning Point in Work to Achieve a Permanent Solution to the Lead Service Line Issue,” August 26, 2019, (Oct. 1, 2019).

8 “How Newark Is Getting the Lead Out,” Sept. 16, 2019, (Oct. 1, 2019).

9 “CORROSION Launches First NACE Podcasts Series: The Flint Phenomenon.” MP, Sept. 16, 2019, (Oct. 1, 2019).

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