Worried that some children may have drunk lead-tainted water at Boston schools, the City Council called Friday for drinking fountains to be shut off at schools citywide. School officials rejected the idea, but said they would listen to councilors’ concerns.

School officials reiterated that all fountains that were active as of Friday had been tested in recent weeks and that the tests had shown no lead levels above regulatory standards.

School Superintendent Tommy Chang has invited councilors to meet with him May 18 to discuss the issue.

“In the interest of continuing a transparent and deliberate process to ensure the safety of our students and staff, BPS remains committed to discussing the issues raised by the council,’’ school officials said.

Most Boston schools are already using bottled water because of lead concerns. Fountains remain in use at about three dozen schools.

In a letter Thursday to Chang and School Committee Chairman Michael D. O’Neill, 12 of the City Council’s 13 members called for a moratorium on fountain use at schools.

“We are outraged at the BPS announcement that some students may have consumed water that was contaminated with lead,’’ the letter said.

The letter called for all fountains to be shut down immediately, and that bottled water be provided until further testing shows they are safe.

In a series of announcements over the past few weeks, school officials have revealed they found lead-related problems in a total of eight schools. Those fountains have been shut off and replaced with bottled water, officials have said.

On Thursday, Chang said school officials were “confident that all active water fountains meet state standards.’’ Chang has said all the active fountains were tested in April and the results were “triple verified’’ by officials from the School Department, city Water Commission, and a third-party contractor.

But the councilors in their letter said the school district had told parents at some schools that the water there tested at acceptable levels, only to later reveal that high lead levels had actually been found.

“It is unacceptable that our young people may have been exposed to unsafe conditions,’’ the letter said.

School officials disclosed this week that at four schools, students may have drunk water with high lead levels because newly installed fountains were mistakenly turned on earlier than they should have been. School officials have blamed the mishap on a lack of communication between its facilities staff and a third-party contractor.

Officials had previously said none of those fountains had been turned on after being installed. On Thursday, officials said that two facilities department employees had been placed on administrative leave as officials investigate the issue.

The fountains were being turned on as part of a plan launched last year to try to restore fountains for use at more schools to save money the district spends to provide bottled water. School officials recently put the brakes on the plan.

About 90 Boston schools already use bottled water because of concerns about lead seeping into the water from aging plumbing. Bottled water is expected to cost the district $415,000 this school year.

Matt Rocheleau can be reached at matthew.rocheleau@globe-.com. Follow him on Twitter @mrochele.