Inverness Public Utility District officials had good news last month: in the most recent round of water tests ordered by the State Water Resources Control Board, just one of 20 samples showed elevated lead levels. Last fall, three residential water samples in Inverness turned up with lead levels that exceeded the federal limit, prompting the water board to require increased testing to determine if the problem was pervasive.
“We take lead contamination very seriously: there is no known safe level of lead,” Zachary Rounds, an associate sanitary engineer for the water board, said. “With regards to Inverness, however, the risk of lead is not acute... Once we have all the data, we can decide the appropriate measures to take.”
IPUD has had exceedances from time to time since it started lead testing in 1994, according to Wade Holland—who served as the general manager from 1985 and 2001 and is currently helping to fill that position—but last year was the first time it received a violation for failing to prove that at least 90 percent of the samples met federal standards.
Per the instructions handed down from the water board last fall, the district must continue to test every six months and pass another round as early as April.
At the district’s last regular meeting, at the end of January, IPUD reported that December tests produced just a single exceedance; two exceedances were allowable. Jim Fox, the district’s operations manager, said the district will continue to complete the testing until it receives further instructions from the board.
Mr. Fox was more guarded last fall when the lead issue first surfaced, but more recently confirmed that the district has noticed an increase in water corrosivity since 2014, when it installed a new nanofiltration system. The system’s fine filter is known to make water more aggressive, pulling metals like lead and copper from pipes and other home infrastructure.
“We asked if we could take precautionary measures as soon as we installed it, such as putting orthophosphates into the water, but the state told us that we needed to actually fail testing before they wanted us to do that,” Mr. Fox said. “I’m also reluctant to start adding chemicals to the water.”
In the past, the district had been troubled by problematically high levels of disinfection byproducts—known as DBPs—a result of using chlorine to disinfect the water. To remedy that problem, IPUD made the switch to a nanofiltration system at one of its treatment plants in 2014 and at the other in 2016.
Mr. Fox said the resulting increase in corrosivity was not as great as the district had anticipated, and it is not clear to him from the lead and copper testing—as well as from other regular tests the district completes for the water board—that there is a systemic problem.
If the district succeeds in passing its next round of testing, IPUD will make efforts to relax the monitoring by applying for a state waiver, he said.
Mr. Fox emphasized that the town’s source waters show no lead contamination, and cautioned customers against taking extreme measures, such as running taps for minutes on end.
“In five seconds—15 if you think you might have lead-based solder—any lead that might be there is gone,” Mr. Fox said. A notice sent out by the district in October suggested running water for 15 to 30 seconds, but Mr. Fox suspects people might be running taps for a few minutes or more.
“People hear lead and they immediately think the worst, but we are talking parts per billion here,” he added.
The tests that first got the water board’s attention were drawn in April 2018. At that time, three of 25 samples exceeded the limit established by the Environmental Protection Agency—15 parts per billion—at 21 ppb, 44 ppb and 45 ppb.
The state’s notice of IPUD’s transgression last September stated, “The change in treatment at both water treatment plants and the elevated lead concentration raise the concern of corrosion and possible health risks.” The board required the district to notify the public of the dangers of lead and undertake further testing.
IPUD was already on an increased schedule, however. In May 2017, due to concerns that the nanofiltration system was increasing corrosivity, the water board asked the district to increase testing from 10 samples every three years to a minimum of 20 samples every six months.
The district was not immediately diligent in following the state’s orders, and was cited after submitting samples in 2018 that should have been drawn in 2017. (The citation was rescinded after IPUD took efforts to comply.)
Since last year’s samples proved problematic, the district has taken a few measures. It replaced faucets at the three homes in violation, in case that individual infrastructure was leading to the problem. It also downsized its sample size from 25 to the base requirement of 20.
The latest round of testing did include each of the three homes that exceeded levels in April's tests, one of which again surpassed the limit, at 24 ppb, down from 45 ppb in April. Eighteen of the 20 samples came back with no detected lead, and one with levels under the limit, at 6.2 ppb.
IPUD has also been facilitating lead testing for any customers who are interested, though residents must pay a $42 fee to a third-party lab. Mr. Holland reported that out of the nearly 10 tests taken in recent months at customers’ request, one showed lead levels in exceedance of the federal limit. (Mr. Holland said he could not disclose the levels.)
Under the state water board’s rules, the minimum 20 samples must be tiered based on the age of the home’s infrastructure. Prompting some concern, the district categorized the home that has had two consecutive violations as tier three—or homes with the newest infrastructure. According to Mr. Fox, it was unlikely there was any lead solder there.
“It’s less common to see lead exceedances in California,” commented Mr. Rounds about IPUD’s dilemma. “Unlike places like Flint; Washington, D.C.; or Chicago, where there are lead service lines, the primary concern is lead in the fixtures, which some homes still have.”
Since 1986, the Safe Water Drinking Act has prohibited the use of any solder, pipe, plumbing fitting or fixture in all water systems and facilities providing water for human consumption that is not “lead free.” As amended in 2014 in response to the Flint, Mich. water crisis, the E.P.A. redefined “lead free” fixtures from having a maximum lead content of 8 percent to a maximum content of 0.25 percent.
According to the Centers for Disease Control and Prevention, “Most studies show that exposure to lead-contaminated water alone would not be likely to elevate blood lead levels in most adults, even exposure to water with a lead content close to the EPA action level for lead of 15 parts per billion (ppb).” Yet it continued, “Risk will vary, however, depending on the individual, the circumstances, and the amount of water consumed.”
Elevated levels of lead, a powerful neurotoxin associated with decreased IQs and other cognitive and behavioral problems, affected thousands of children in Flint in 2014. Samples taken from homes there ranged between 200 ppb and 13,200 ppb.
Under the E.P.A.’s lead and copper rule of 1991, which was amended in 2000 and 2007, the maximum contaminant level is 15 ppb for at least 90 percent of the samples. The rule requires steps to “optimize their corrosion control treatment” if this standard is not met.