But tap water in the recent Newark, N.J. field tests reportedly contained much higher lead levels.

PUR faucet-mounted filter products are certified by NSF International to reduce lead to below 10 parts per billion (ppb) when challenged with water containing 150 ppb lead, which is 10 times the U.S. EPA action level.

“But the data we have seen so far indicates that some of the tap water from the homes sampled in Newark had lead levels far higher than what anyone would expect,” said Dave Purkiss, vice president of NSF International’s water programs. “It’s a very unusual situation.”

In some cases, the tap water from leaded service lines in Newark appears to exceed 1,500 ppb lead – 10 times higher than the lead level required for challenge water used during certification testing under NSF/ANSI 53.

“Differences in local water chemistries can also affect both the leaching of lead from pipes and the performance of filters,” Purkiss said.

NSF International’s certification requirements – including its lead reduction criteria – are described in the standard NSF/ANSI 53: Drinking Water Treatment Units – Health Effects, which was developed by a committee of experts representing the regulatory community, industry, academia and users.

Water filters certified by NSF for lead reduction are evaluated using water that contains 150 parts per billion (ppb) of lead. This lead concentration is 10 times higher than the U.S. EPA action level for lead in drinking water. The filters are challenged at this level of contaminated water to simulate typical use during and beyond the filter’s claimed service life cycle. Certification is only confirmed when the product has met all lead reduction requirements and other requirements of the standard. To maintain certification, NSF certified products are retested periodically, and NSF audits the appropriate manufacturing facilities every year. The testing is conducted at NSF International’s ISO/IEC 17025-accredited laboratories located in Ann Arbor, Mich.

In addition to the amount of lead in the tap water, the performance of any water filter depends on proper installation, maintenance and replacement according to the manufacturer’s use instructions.