Household brass plumbing fixtures may release far more lead into drinking water than previously believed, according to a report coauthored by Marc Edwards, a professor in Virginia Tech's Department of Civil and Environmental Engineering. Edwards is an internationally recognized expert on lead contamination, who in 2003 was the first to alert officials in Washington, DC, to dangerously high levels of lead in public water.
The report suggests that the standards used to certify consumer brass plumbing supplies may be inadequate to predict lead contamination of water; even new homes constructed using the latest brass fixtures like ball valves and water meters might lead to potentially unsafe lead levels. Plumbing supplies sold today are not lead-free; they can contain up to 8% lead by law.
Research team members included three researchers from Virginia Tech and one from the U.S. EPA. They focused on one area of NSF standards dealing with "in-line" plumbing such as ball joints, check joints and water meters. Products that pass the current NSF testing process receive the ANSI/NSF 61-8 certification.
The crux of the report is that the researchers question those testing procedures and the accuracy of the results. Essentially, the team's criticism focuses on the two-pH levels in the testing water. They report that the one level was too low to draw lead out of the brass—and that the higher pH loses its leaching effectiveness after several days.
They also report that the testing water also contains an additive that suppresses lead leaching—but that additive is not universally used by municipal drinking water systems.
Consequently, the team says those three factors mean that current standardized tests may not accurately reflect average in-home water conditions and may not be sufficient to protect public health.
If true, the report would contradict years of assumptions that lead contamination primarily comes from lead pipes or public water systems with lead contamination problems.