Families of Boston Public School students will be briefed by school officials at two meetings early this week after water fountains being tested for lead exposure were mistakenly left operational, officials said.

Four facilities — including Dorchester's Mather School on Meetinghouse Hill and the Lee K-8 School on Talbot Avenue— were found to have lead levels 15 ppb (parts per billion), the level at which the Environmental Protection Agency recommends action to reduce the lead exposure.

Most Boston Public Schools use bottled water on the premises due to past lead concerns. Boston had been in the midst of replacing fountains at a number of schools, which stalled when high levels of lead were discovered in some of the new fountains, BPS officials said.

The school department said 38 of the 126 BPS facilities (those with active water fountains) were tested in recent weeks, “and the results have been tripled verified by Boston Public Schools, Boston Water & Sewer Commission, and a third-party contractor.”

The lead contamination crisis in Flint, Mich. has sparked concerns and investigations in city and school water systems across the country.

A analysis of the Flint water study in August emphasized that while the 15 ppb measure is for regulatory purposes, there is no guaranteed safe amount of lead to be consumed in drinking water. Children and pregnant women are among the most vulnerable to the effects of lead exposure, which can result in a host of physiological problems.

School officials initially reported that all impacted fountains had been inactive since their installation, but last week revealed that four schools had fountains turned on earlier that they should have been. In addition to the Mather and Lee schools, impacted schools the Curley K-8 School in Jamaica Plain and Another Course to College in Brighton.

According to BPS, the Mather Elementary school had water fountains left "online" for three weeks. The other schools' fountains were “online” between 12 hours and one week.

“These fountains were turned on prematurely due to a miscommunication from the BPS Facilities Department,” the school department said in a media advisory.

Two BPS Facilities Department employees, who have not been identified, were placed on administrative leave as a result, officials said.

Information sessions for families will be held on Monday, May 9 at 6:30 p.m. and Tuesday, May 10 at 8 a.m. at the Bolling Building, 2300 Washington St., Roxbury, MA in the second floor School Committee Room.

BPS has made a water safety website available, including lead fact sheets and lead testing levels in Boston schools, at bostonpublicschools.org/water.