Of all the things parents might worry about at their children's school, the water bubbler wouldn't usually rank high.

But a new report from two public health advocacy groups may change that.

Lead showed up in almost half of 40,000 school taps tested in Massachusetts, according to the report from the Environment America Research & Policy Center and U.S. PIRG. The report, which examined lead issues in schools in 16 states, concludes that current Massachusetts laws are not strong enough to protect children from lead in school drinking water.

That's also something that may change.

Two state legislators, Rep. Lori Ehrlich and Sen. Joan B. Lovely, both of Essex County, are filing bills that would require regular water testing in schools and daycare centers, the removal of lead supply lines and the installation of filters on faucets and fountains. Testing is currently voluntary — one reason the report's authors gave Massachusetts a D on lead safety in schools.

"The grade of D is certainly shocking, but not all that surprising," Ehrlich told WBUR Thursday. It's not surprising, she explained, because the infrastructure here is old; water lines were coated with lead before people understood its dangers.

But it is dangerous, especially to children.

"We know from study after study that high exposures reduce children's IQ scores," said David Bellinger, a Harvard Medical School professor who has studied lead's health effects since 1979. "It's really incontrovertible at this point."

Lead exposure has also been linked to attention deficit and hyperactivity disorder, along with other behavioral and cognitive issues.

"All of these things together lead children to be less successful in school," Bellinger said.

But people often don't think about water when they're worrying about lead, he said. Instead, there's a false "perception that the lead problem has been solved because we took it out of gasoline and it's no longer in paint."

"The idea that we've dealt with the problem is overly optimistic," Bellinger said.

Asked whether she thought her legislation — which would likely require water authorities to pay for infrastructure upgrades across the Commonwealth — had a chance of passing, Ehrlich pointed to 79 of her State House colleagues who, she said, have signed on as cosponsors.

And, she said, it helps that safe water is the ultimate bipartisan issue.

"It cuts across politics, across demographics," Ehrlich said. "We can't live without it."