MINNEAPOLIS — Testing for lead in drinking water at some Minnesota schools hasn’t been done since the late 1990s despite a state health recommendation that it be done every five years.

Among water testing records of more than 600 Minnesota schools, at least one out of every four of those schools are not testing based on the Minnesota Department of Health’s recommendation.

Records show Minneapolis Public Schools hasn’t tested at least 31 of its schools since 1998, though district officials say they are following the state’s guidelines for flushing water lines to reduce lead levels.

“It’s a little surprising to me to hear that there are systems that have not been tested for very long periods of time,” said Paul Allwood, assistant commissioner of health.

Allwood noted that the department’s guidelines are voluntary. Allwood said the department is discussing whether there should be an additional authority over school water testing.

Minneapolis custodians are supposed to run the fountains and drain lines for 10 minutes every school day in the morning and sometimes later in the day. Lee Setter, who oversees the district’s Lead In Water Safety Program, said the district trusts its employees to follow the protocols.

“We’re not out in every building every morning but I think most people in our district understand the importance of it,” Setter said. “We have a very comprehensive program to identify our hot spots where we need to really focus on this,” Setter said.

Records show the South Washington County school district, which includes the cities of Woodbury and Cottage Grove, has not conducted lead water testing since at least 16 years ago, KSTP found.

District officials initially blamed the high cost for not following the state guidelines. However, they later told the station in a follow-up email that they would be “moving forward with water testing over the course of the 2016-17 school year.” They estimated the testing would cost $43,000 and said they would “immediately address” any issues they discovered.

Municipal water systems already test for lead in the water they deliver, but health officials suggest that schools test themselves due to possible sources of lead inside their plumbing, such as lead solder and brass fixtures, that could contaminate the water that students drink.

“Parents really need to hold schools’ feet to the fire to make sure this problem is fixed,” Edwards said, adding that it costs as little as $30 to fix water fountains with high amounts of lead coming out of them.