Latest Inverness lead tests come back under limits

09/05/2019

Inverness Public Utility District officials celebrated the results of another clear round of lead and copper testing last week. The State Water Resources Control Board reported to the district that just one out of 20 water samples drawn this spring showed elevated lead levels, which is allowable under federal regulations. The one offending Inverness residence—which has consistently shown lead levels that exceed the Environmental Protection Agency’s limit—does not cause the district to violate that agency’s standards , which permit the district up to two exceedances per sampling. The recent results were welcomed by the district, which has been under increased surveillance from the water board. Last fall, three residential water samples turned up with higher-than-allowable lead levels—a violation that prompted the state board to require further testing to determine if the problem was pervasive. The district was already on an increased schedule, however, given concerns from the water board that a nanofiltration system IPUD installed in 2014 might increase the corrosivity of Inverness water. The district has had lead exceedances from time to time since it started testing in 1994, but last year was the first time it failed to prove that at least 90 percent of the samples met federal standards. The most recent tests, from May, yielded one exceedance: at 17 parts per billion, just above the EPA’s cap of 15 ppb. The previous set of samples, drawn in December, also had one exceedance from the same house, at 24 ppb. Last year, that house showed much higher lead levels, at 44 ppb, and was joined by two other houses with exceedances, at 21 and 45 ppb. IPUD employees took several measures since last fall, primarily replacing old faucets at the sampled homes to eliminate home infrastructure as a possible factor. It also reduced the sample size from 25 to 20 homes and facilitated lead testing for customers who requested it. In a letter sent in July, water board engineer Janice Oakley told district officials that they were eligible to reduce testing to once per year and to halve the number of samples. The next testing is scheduled for next summer. At last Wednesday’s meeting, IPUD board members were quick to celebrate, even deciding it likely wasn’t worth letting customers know about the testing results. “I think we were clear all along,” Dakota Whitney said. “[The problem] was not us delivering water with lead in it but, in certain homes, and so to me this isn’t really newsworthy." This newspaper published several stories that drew the link between the exceedances and the nanofiltration system, which the water board indicated could increase the overall corrosivity of the district’s water. The system’s fine filter is known to make water more aggressive, pulling metals like lead and copper from pipes and faucets. Additives such as orthophosphates are a common solution to corrosive water, though the water board is responsible for determining the need for any mitigation measures. In the meantime, for the offending house, district representative Wade Holland told the Light, “The faucet was replaced, so we think the problem is further back, in the plumbing. We are advising them to run the water for a few seconds before they drink it. They have been very cooperative.”