Two independent chemistry experts say lead could be more widespread in Asheville’s drinking water following Tropical Storm Helene than the city has suggested and both call for more public education and testing.

Sally Wasileski, chair of the UNC Asheville chemistry department, and Abigail Cantor, a chemical engineer and president of Process Research Solutions, LLC, which consults on municipal water issues, said they recommend residents of homes built in or before 1988, when lead was banned in new plumbing, use bottled water until they test their water.

“We cannot risk widespread lead poisoning, especially on top of all that our community has faced in the wake of Helene,” Wasileski wrote in a letter to the media and larger community in November. “We need a broad investigation of the lead levels at the tap of residences, schools, and businesses who source their water from Asheville City Water.”

Cantor, who lives in Madison, Wisconsin, has relatives in Asheville and said she warned them about the risk of lead in the water.

“I’ve told them not to drink the water yet, until I test their water,” Cantor said.

Wasileski and Cantor reached out to Asheville Watchdog independently of each other and stressed a measured approach and the need to base decisions on test results.

“I understand that it is very important to not cause a panic,” Wasileski wrote in her letter. “Yet clear and effective communication, and widespread testing will ensure that there is not a second crisis across Asheville and Buncombe County.”

Asheville Water Resources Department spokesperson Clay Chandler said city water is safe to drink.

“The water meets EPA drinking water standards and is acceptable for consumption,” Chandler said.

“If a customer is pregnant, nursing, or has children under 6 years of age, and has concerns about lead exposure, they’re free to use bottled water for consumption or install a filter certified by the National Sanitation Foundation to reduce lead,” Chandler said.

The city also stressed that its distribution pipes do not contain lead, and it has no detectable lead in its main reservoir. 

James Pinckney, an EPA spokesperson, said the agency continues to work closely with Asheville and the North Carolina Department of Environmental Quality on their response efforts, “including their plans to test and report on lead.

“The city has not violated the Safe Drinking Water Act’s Lead and Copper Rule at this time, and they are voluntarily conducting investigative lead sampling in the system post-hurricane to evaluate the aftereffects that the hurricane has had on the system and ensure the safety of the residents,” Pinckney said.

Lead is a powerful neurotoxin that can cause developmental problems in children. No level is safe in a water system. 

Since the city announced Nov. 14 the presence of lead in the water of seven schools, it has received more than 5,000 requests for home lead testing kits. It takes four to six weeks to receive the results.

Lead levels rise in pipes when water has been sitting for a while. The city has stressed the importance of flushing residential plumbing lines for 30 seconds to two minutes to help remove lead. 

Lead mitigation halted for 19 days

The city normally treats for lead with zinc orthophosphate and sodium bicarbonate. The minerals coat the insides of pipes, with the zinc material absorbing the lead and keeping it from reacting with water; the bicarbonate helps with pH levels.

The corrosion control treatment prevents lead, used in solder in pipes in homes and buildings built in 1988 or before, from leaching into the water. Some older homes also have lead pipe service lines. The city has said about 60 percent of Asheville homes were built in 1988 or earlier.

The Asheville Water Resources Department said in mid-November that it had stopped the treatment for 19 days in October as it worked to restore water following Helene.

The treatment was suspended because sedimentation at North Fork Reservoir, the city’s main water source, was unusually high and the city was using a bypass line to get water out. Treatment resumed Oct. 30, but it can take a month or more to become effective again, the city said. 

The city returned non-potable water to most customers by mid-October but told them to use bottled water for consumption — unless they had no access to it, in which case they could boil the tap water for at least a minute before consuming. Boiling water does not remove lead, which has no taste or smell.

Water Resources received initial lead test results Nov. 4 and final ones Nov. 8. The city shared those Nov. 14, announcing seven local schools tested positive for lead.

Chandler emphasized that out of 25 sites tested at schools, those seven had detectable lead levels “on the first draw — meaning, water that had been sitting stagnant for multiple weeks was tested straight out of the pipe, with no flushing beforehand.

“After a 30-second flush, six of those fell below detectable levels,” Chandler said. 

Water Resources and Dr. Jennifer Mullendore, medical director for Buncombe County’s Department of Health & Human Services, stressed that students were not exposed to lead, and there have been no reports of students with lead in their bloodstream.

The coating in pipes is the key

A key concern for Wasileski and Cantor is the damage or compromise that the protective coating of zinc orthophosphate may have sustained during the water outage and the suspension of treatment.

In her letter, Wasileski noted that water chemistry is complex and “changes due to factors like pH, oxygen content, chlorination, temperature, mineral levels.”

“Any small breaks in this protective coating would now enable water to come in direct contact with lead metal in the pipes and fixtures, and cause this lead to corrode and leach into the water flowing into and through home plumbing,” Wasileski said, citing EPA information. “What is unclear is how much damage to this protective layer can be caused by the 19-day lapse in corrosion control.”

Wasileski did note that most case studies of elevated lead levels “are from plumbing damage over longer periods of time.

“Even in these cases, the extent of lead corrosion was highly variable as the protective coating of some fixtures and pipes had more breaks (and leached more lead) than others,” Wasileski wrote.

The city’s positive results for lead, she noted, were “well above the amount of lead recommended for action by the American Academy of Pediatrics. 

“The new lead test results indicate the likelihood of damage to the protective coatings in these schools’ plumbing and fixtures, or damage to their water service lines,” Wasileski wrote. “In addition to the risk of lead in water at these schools, these results also indicate the potential for more widespread damage to plumbing in residences and businesses across the city.”

The risk of exposure, Wasileski said, remains because “it is well known that the time it takes to regenerate this protective layer once corrosion control has resumed is highly variable and can take years to form.” She cited an EPA document in her letter. 

Chandler, citing guidance from the EPA, said coating regeneration takes 30 to 90 days. 

Cantor, who has been a consulting engineer since 1981 and has specialized in distribution system water quality since 1991, said she agreed with Wasileski’s call for more lead testing in water and for people via blood tests. She’d also like to see better communication and a recommendation that people in older homes not drink tap water until they test for lead. 

While zinc orthophosphate can form a protective film on the pipe walls that will slow down or stop further corrosion of the pipe, Cantor said, “if pipe walls are already obscured with chemical scales and biofilms, that protective layer cannot form properly.”

She says this applies to all pipes in a water system, whether city-owned or privately owned, although most significant sources of lead occur in private plumbing.

Water in municipal systems is a mixture of chemicals, microorganisms, minerals and organic matter that interact with biofilms and chemicals on pipe surfaces. Biofilms emit secretions and chemical byproducts that can alter the water chemistry in the distribution system, leading to corrosion of pipe metal.

Cantor said the interactions can cause problems with water quality, including lead and copper release.

Another factor to consider, Cantor said, is that federal regulations require measuring total lead concentration in water — the dissolved lead plus lead in particulate form. But the orthophosphate treatment controls only the dissolved lead concentration.

If the lead is in particulate form, it has been released from pipe accumulations, not from metal corrosion directly.

“It is from release of pipe wall accumulations where the lead has been trapped,” Cantor said. “Orthophosphate will not remedy that situation. Orthophosphate is irrelevant to controlling particulate lead.”

That’s why thorough flushing is key, Cantor said. She recommends the city engage in a program of intense water main flushing throughout the system, and that it continues with the zinc orthophosphate program, as it does offer some protection. Customers should also intensely flush their own homes.

Asheville’s water likely sat in pipes for days or weeks, and that “great stagnation of water,” followed by the introduction of partially treated water, likely “disturbed pipe wall accumulations and released trapped particulate lead in residences and larger buildings such as schools,” Cantor said.

Chandler said predicting how much the city’s corrosion control was compromised is not possible.

“The potential exists that the corrosion control layer did begin to break down,” Chandler said. “The testing performed at the city and county elementary schools, participating child care facilities, private schools and the private residence show a potential for breakdown, but since only seven of 25 sites tested showed a detection —  and only one showed a detection after a 30-second flush — it does not point toward a complete breakdown in corrosion control during that 19-day period.”

After Helene washed out the two main transmission lines from North Fork and a backup bypass line, the city focused on restoring service as quickly as possible.

“Once our infrastructure was rebuilt, our sole option was to provide hyperchlorinated raw water for critical fire protection and basic sanitation,” Chandler said, noting the water’s condition necessitated a boil water notice. “Throughout the boil water notice, we recommended bottled water for consumption.”

That guidance came directly from the North Carolina Department of Environmental Quality and the federal EPA, Chandler said.

Before lifting the boil water notice Nov. 18, the city tested water throughout the distribution system, and results showed zinc orthophosphate had reached every part of the system. Under EPA guidance, the city increased the zinc orthophosphate from the normal 2.0 parts per million level to 3.5 ppm “to expedite rebuilding the corrosion control layer,” Chandler said.

North Carolina Department of Environmental Quality spokesperson Josh Kastrinsky said its Public Water Supply section “is aware that Asheville has collected some samples outside of its regular compliance schedule at schools and homes.

“The city is taking another round of samples at Buncombe County schools,” Kastrinsky said. “They are developing a plan to respond to the requests for sampling and reaching out to laboratories to determine capacity. Asheville has been coordinating with EPA on potential sampling options. They should provide sampling results to DEQ, when available.”

Kastrinsky noted that Asheville was on a three-year monitoring schedule and collected 50 samples between June and July of this year.

“None of the samples were above the action level for lead or copper,” Kastrinsky said, noting that one sample was at the lead action level of .015 mg per liter. “At this time, Asheville is in compliance with the federal Lead and Copper Rule and has not been issued any citations or warnings related to lead.”

The importance of flushing pipes

Corrosion control is important, Chandler said, but “the easiest and best way to reduce risk of lead exposure is to flush your system” for 30 seconds to two minutes.

The first step to keeping plumbing clean at the user level is to routinely clean water mains, Cantor said. 

The zinc orthophosphate should combine with lead, forming a highly insoluble solid that stays on the pipe and forms a protective layer. But that’s if the pipes are relatively clean.

“What I’ve seen is that pipe walls have so much accumulation of chemical scales and biofilms that the orthophosphate has nowhere to lay down a protective layer,” Cantor said.

She also recommends that homeowners conduct a thorough flushing of their own homes, letting the water run out an outdoor tap first and then running taps on the first floor and then the second. Because plumbing varies from house to house, Cantor declined to give a timeframe on how long to flush.

Wasileski wants to see clearer and more widespread messaging from the city. She recommends widespread testing at the tap for both lead and copper at residences and businesses built before 1988.

She also recommends that residents in these homes use only bottled water until they get lead test results back and advocates immediate blood tests for lead for anyone that consumed tap water since water service returned in mid-October.

“And the need is even higher for children, pregnant or breastfeeding women, and especially for any infants who consumed formula prepared from boiled tap water,” Wasileski said.

She recommends checking the type of water service line to your home by visiting the city’s web page on the issue. That page shows the type of pipe used for service lines and if it contains lead.

More information on the lead issue

The City of Asheville’s webpage on lead and copper testing encourages flushing pipes for 30 seconds to two minutes daily.

“According to guidance from the EPA, flushing is a short-term solution that can be used to reduce potential lead and copper presence in drinking water,” the site states. “Depending on pipe materials, lead and copper may be found in water that has sat undisturbed in household plumbing for 4-6 hours.”

Buncombe County also has a page dedicated to lead awareness and the recent testing issues, titled, “Lead Awareness and Your Health: Q&A with Buncombe County’s Medical Director.”

It states: “Out of an abundance of caution, children under 6, pregnant people, and breastfeeding people who have consumed tap water while the City of Asheville water customers were under a Boil Water Notice, and have concerns, should consult their healthcare providers. If they do not have a doctor, they can call the Buncombe County Blood Lead Information Line at 828-250-5205.”

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. John Boyle has been covering Asheville and surrounding communities since the 20th century. You can reach him at (828) 337-0941, or via email at jboyle@avlwatchdog.org. The Watchdog’s local reporting during this crisis is made possible by donations from the community. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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Today’s round of questions, my smart-aleck replies and the real answers:

Question: There have been various estimates as to the magnitude of the Helene flooding in the French Broad watershed. Some have said it was the 100-year flood. Others have said it was the 500-year flood. The determination is actually fairly straightforward. The calculation can be done for each specific river-gauging station. It is based on the historic record of each year’s highest stage (river level) as recorded at that gauge station. Its accuracy is obviously a function of the length of the record. The longer the record, the greater the statistical soundness of the estimate. The 100-year flood, as you probably know, has nothing to do with 100 years. It is just the flood level that has a 1 percent chance of occurring in any given year. The 500-year flood has a .2 percent chance. The longest gauge record for the Asheville region, based on the U.S. Geological Survey national water data dashboard, appears to be the one on the French Broad River at Asheville. Gauging data are also available on the USGS WaterWatch website. One site says there are discharge data starting in 1985. Another site says the record extends 128 years.  Neither site currently appears to be capable of downloading the data set. Can you ask whether anyone has actually determined the nature of the Helene flood at that station? It probably wasn’t the 100-year flood or the 500-year flood, but rather something in-between. A followup question would be how the 2024 flood will cause a reset in the determination of the 100-year flood level for that gauging station.

My answer: I’m going with “one-bazillion-year flood,” mainly because I never want to see another one of these. 

Real answer: This is a topic that keeps recurring here, and from what the experts tell me, it certainly seems like a 1,000-year rain event. Whether that translates into a 1,000-year flood event remains a little bit of a gray area.

Nathan Pennington, Buncombe County’s planning director, opened this can of worms at the Nov. 20 daily Helene briefing during a discussion about floodplain management and the National Flood Insurance Program. As Pennington mentioned, the county partners with the state on FEMA flood mapping, with the upshot being the state draws the flood maps for Buncombe.

He showed maps of the Swannanoa area that show the most at-risk section, marked in purple and called the floodway, which are areas that “almost always flood during a rain or storm event.” The next area, in blue, is the 100-year flood area.

“Development is allowed in this area, but standards must be met,” Pennington said, noting that, as the reader said, this means these areas have a 1 percent annual chance of flooding. 

Next, in green, was the 500-year flood area, which as Pennington and the reader noted, simply means it has a .2 percent annual chance of flooding.

“What we saw during this event was flood water that so far exceeded the 500-year (flood), it’s very likely we experienced a 1,000-year event, which is not even mapped,” Pennington said.

It’s important to note he said “very likely,” and that he was referring to one area of Swannanoa.

As the reader noted, the U.S. Geological Survey does track river gauge data, so I checked in with public affairs specialist Alexandra Hays to see if it had made a determination, based on the gauge the reader mentioned or any others.

“So, the National Weather Service actually sets the historical designations of ‘100-year-flood, 500-year-flood,’ etc., so to find out how they determine these, you’d have to reach out to them,” Hays said.

More on that in a second.

Like everyone who addresses this topic, Hays also stressed the notion of how “100-year flood” can be misleading. In fact, the USGS has prepared a document on this aptly titled, “The 100-year flood.” 

“Hydrologists don’t like to hear a term like ‘100-year flood’ because, scientifically, it is a misinterpretation of terminology that leads to a misconception of what a 100-year flood really is,” the article states, noting that instead hydrologists would say it’s a flood having a 100-year recurrence interval. That’s where the 1 percent chance comes in.

“That being said, we use the term ‘Annual Exceedance Probability’ to track the flooding at individual streamgages, and our teams are still in the process of collecting the needed data to compute the AEPs in areas affected by Helene,” Hays said. “One of our surface water specialists tells me we are going to publish a report of the AEPs for our streamgages in the area for Helene, but it will be a few months before that is available.”

Next, I called up the National Weather Service and spoke to meteorologist Jake Wimberley. Regarding the flood information being given out, Wimberley noted there were “a lot of differing numbers” coming out, because rainfall varies from point to point.

“There were unofficial statements that were really extreme in terms of how rare the event was, so I don’t want to lead you astray,” Wimberley said.

The best source is the National Oceanic and Atmospheric Administration’s data compendium called the Atlas 14 project. That includes analyses that show how much rain would fall at a given point, and how frequently that is expected to recur, which is where the idea of the 100-year event comes from.

Wimberley pulled up data for Asheville Regional Airport, the official recording station for the area. 

“So, the airport got 14.19 inches of rain during Helene — the precipitation event that led up to Helene, and the actual passage of the storm,” Wimberley said, noting it was technically listed as a four-day event, although rainfall was very light on that first day.

The 1,000-year measurement for a four-day event would be 11.6 inches.

“So we were over that,” Wimberley said. “And this is for one specific point. I could look at different points and come up with different numbers.”

Indeed, we know rainfall was heavier in certain areas. For instance, Busick in Yancey County recorded 30.78 inches, and Mount Mitchell State Park recorded 24.20 inches, according to a Nov. 7 article on NOAA’s Climate.gov site. 

“Estimated rainfall totals from Helene across the southern Appalachians had an Annual Recurrence Interval greater than 1,000 years over a wide area; meaning there is less than a .1 percent chance (annual exceedance probability) of that happening in any given year, according to NOAA’s National Water Center,” the article states.

So that’s indicative of a 1,000-year event.

The North Carolina State Climate office also had an article about Helene that cited the Atlas 14 information, noting that it is “imperfect due to its lack of recent updates.” The office used a three-day measurement of rainfall.

“In Asheville, the three-day total of almost 14 inches goes well beyond the 1-in-1,000 year total for a 72-hour period, which Atlas 14 cites as 11.4 inches,” the article states. “Likewise, the 24.41 inches over three days at Mount Mitchell is off the charts compared to the noted 1-in-1000 year amount of 16.5 inches.”

So, as Wimberley puts it, “The full event in total looks like there were multiple places that it was more than a 1,000-year” rainfall event.

“They haven’t come up with data for more than a one in 1,000-year event,” he added.

Clearly, that much rain translates into a lot of flooding, but it’s tougher to nail down that “1,000-year” designation.

“These major, major rainfall events usually translate to some flooding,” Wimberley said. “But I think it’s more accurate to say this was a 1,000-year rainfall event, as opposed to a 1,000-year flood event.”

Now, as far as Helene causing some kind of “reset” with the data, I contacted David Easterling, director of the National Climate Assessment Technical Support Unit at the National Centers for Environmental Information in Asheville.

“Bottom line is that the National Weather Service is producing a new version of NOAA Atlas 14, which will have both Volume 1 with new values based on the historical observed data, and Volume 2, which will provide estimated values for the future based on climate model projections,” Easterling said.

That means it will include projections related to climate change. Easterling did offer one caveat, though.

“I suspect the Weather Service is far enough along in their data analysis that they may not include Helene, since they expect to release Atlas 15 in 2026,” he said.

Question: We live in Weaverville, in the Reems Creek Golf Community, and we were all incredibly fortunate not to have suffered much in the way of damage to our homes. Our tree-covered streets and homesites, however, lost dozens if not hundreds of trees. While many of them, due to the extensive rainfall before Helene ever hit, were simply toppled from the roots, there were also many that were snapped clean in half at mid-trunk, often with a corkscrew pattern in the wood. This leads us to think that there might have been micro-bursts of mini-tornadoes spawned by the storm. Has there been any official determination to that effect? 

My answer: I have micro-bursts of energy these days. It’s the only way I get the Answer Man columns done.\

Real answer: Michael Rehnberg, a National Weather Service meteorologist, said we did not have documented tornadoes in the mountains with Helene. The strongest winds hit around sunrise Sept. 27.

“We had a swath of really strong winds that moved right up the Upstate and then over the state line from South Carolina into North Carolina, and affected a lot of areas in the mountains and the foothills in North Carolina as well,” Rehnberg said. “But those were non-tornadic winds.”

Rehnberg noted that the wind gusts data for Helene has not been certified by the National Centers for Environmental Information, so the numbers are still considered preliminary.

“But all across the Upstate, at least, of South Carolina, and into the southern mountains of North Carolina, there were varying reports of winds over 60 miles an hour,” he said.

That’s clearly strong enough to take down trees, especially with the amount of rain that had fallen over three days, leaving the ground saturated. That can turn root balls into mud, making even large trees vulnerable.

“So when you combine that with higher wind speeds, you can see just kind of the mass devastation — I mean, hundreds, thousands of trees down across these large areas,” Rehnberg said. 

The winds were also most devastating on south-facing slopes, as that’s how the storm traveled, from south to north.

A microburst is unlikely to have occurred with this event, Rehnberg said. In a microburst, contracting air aloft descends very suddenly. 

“The physics behind that are really closely associated with the way that thunderstorms develop, as opposed to tropical systems,” Rehnberg said. “But that’s not to say that you couldn’t have had very high winds, certainly winds capable of producing the really erratic gusts at the surface.”

Our terrain can play a role with high winds, though, and gusts reaching up into the 60s or maybe higher can cause major, and unusual, tree damage.

“In particular, when you’re dealing with the kind of terrain that you have up in the mountains, what can start out as a simple, straight line wind can simply become very erratic just because it’s responding to all of the rolls and dips in the actual terrain up there,” Rehnberg said. 

He would attribute those twisted-looking trees to that phenomenon, he said, not tornadoes.

I’ll note that several sources online, including one academic study, suggest trees will start to break under wind speeds of about 90 mph. But I suspect some other factors could come into play at times, including health of the tree.

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. Got a question? Send it to John Boyle at jboyle@avlwatchdog.org or 828-337-0941. His Answer Man columns appear each Tuesday and Friday. The Watchdog’s reporting is made possible by donations from the community. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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