Elevated lead levels were discovered in 14 locations that receive their drinking water from Trenton Water Works.

This story has been updated to include additional information from the Department of Environmental Protection.

Trenton Water Works found elevated levels of lead in drinking water in some Mercer County homes and buildings, according to a notice mailed to customers earlier this week.

During routine testing, Trenton Water Works—a company that provides water to Trenton as well as parts of Ewing, Hamilton, Lawrence and Hopewell—found elevated levels of lead in 14 different locations.

These locations tested higher than the Environmental Protection Agency’s “action plan” of 15 parts per billion. According to the EPA, if drinking water tests higher than 15 parts per billion, then additional testing and remediation is required.

Of the 14 locations with elevated lead levels, six were found in Trenton, four were found in Hamilton, three were found in Lawrence and one was found in Ewing, according to the state Department of Environmental Protection. Most of the elevated lead levels were between 16-30 parts per billion, but one result had levels of 106 parts per billion.

Trenton Water Works is required to periodically test 100 properties, and they recently tested more than 100 properties across the towns they serve. Since more than 10 percent of the test results were above the “action level,” federal regulations required Trenton Water Works to notify all of their customers.

Hamilton Township Mayor Kelly Yaede said in a statement that the company did not contact town officials to alert them of the elevated lead levels, and she first learned about the issue after residents began receiving the notice in the mail. The township’s health officer is currently working with the state DEP to learn more about the implications of the elevated lead levels.

Lead enters drinking water primarily due to corrosion of materials containing lead in the water distribution system and household plumbing, according to the Trenton Water Works notice. This includes service line pipes—pipes connecting houses and buildings to the water mains—made of lead, lead-based solder used to join copper pipe, and brass and chrome-brass faucets.

Testing water for lead contamination is typically a multi-layered process, with multiple tests done to determine if there is lead in water, and if so, where the lead is coming from. Once companies determine if the lead is coming from a service line or a fixture within a building, they can begin work to remove the source of the lead.

Trenton Water Works is in the preliminary stages of implementing a corrosion control study, which will help reduce lead levels by identifying problem areas.

Most household filters do not remove lead, but there are other ways to reduce exposure to lead in drinking water. According to state DEP, if water has been sitting in pipes for a few hours, residents should let cold water run from the tap for roughly 30 seconds before using it for drinking or cooking.

Trenton Water Works also recommends using cold water for cooking, as hot water can dissolve lead quicker than cold water. It is safe, however, to bathe in the water.

The notice urged customers to call Trenton Water Works at (609) 989-3640 or visit their website for more information. For additional information on reducing lead exposure at home, visit the EPA’s website.