It's a classic schoolhouse scene: Thirsty children line up after recess, stoop at hallway drinking fountains, and gulp down cold tap water. But in the Boston public schools, the youngsters are more likely these days to gather like little office workers around a 5-gallon cooler, paper cups in hand.
That's because about three-quarters of the city's schools lack traditional water fountains, a Globe review found. Most were removed from service in 1988 when tests showed that water from aging school buildings contained potentially dangerous levels of lead.
For a generation, the school department has supplied bottled water, at a rising cost to the city, which spent more than $411,000 on water and cups in the 2013-2014 school year, up from $270,000 five years before.
Sarah Heffernan, who has a daughter at the Edward Everett School, said the current system doesn't make sense.
"I couldn't even imagine that bill — what we're spending on water — when we have the best water in the country," she said, referring to a national survey praising the taste of Boston's tap water.
Jill Carter, executive director of Boston Public Schools Health and Wellness Department, said it has been working to improve water access.
"We absolutely know that healthy students are better learners, and our goal really is to create schools where the healthy choice is the easy choice," Carter said. "We see drinking water access as being an important part of that."
This summer, the city is set to begin phase one of the process of repairing old plumbing and installing new fountains, which cost about $1,000 to $1,500 per unit, at six schools: the Curley K-8 School in Jamaica Plain, Boston Green Academy and Another Course to College in Brighton, and Lee Academy Pilot School, Mather Elementary School, and the Trotter Innovation School, all in Dorchester.
Cost estimates range from $36,000 to $85,000 per school, with a total just under $300,000.
Parents at schools set for upgrades lauded the plan, but some wondered why it had taken close to three decades, and how much longer it will take before the city's 87 other schools using bottled water return to the tap.
"If you do six a year, that's a long process," said Katie Fitch, who has two daughters at the Curley K-8 School and serves on the health and wellness committee of its school parent council.
State law requires schools to make water available, with at least one water source for each 75 students. The School Department says it is in full compliance with the law and that many schools have more water coolers than required.
Many parents give their children bottled water to carry to school, and in some schools, the department encourages the use of bottles and offers bottle-filling stations.
A statewide analysis of Massachusetts schools in 2010 found that using a water fountain was half as expensive as using water coolers, according to a study published in the American Journal of Preventive Medicine.
Boston is not the only urban school system to face water problems. In 2007, the Baltimore City public schools halted efforts to remove lead from its water and instead began providing bottled water to all schools. As it renovates schools, officials said this week, Baltimore is installing new filtration systems, eliminating the need for bottled water.
Locally, lead pipes have not caused many issues for schools. Department of Environmental Protection spokesman Ed Coletta said in an e-mail that it "doesn't seem to be a pervasive problem" in Massachusetts.
He cited only one school system, in Braintree, that had problems with lead in water fountains.
In contrast to Boston's schools, other schools in the area are pleased with their access to water. The Springfield school system, for example, has a "really stellar water supply" said spokeswoman Azell Cavaan.
Boston parents say there is enough water most of the time, but schools occasionally run short between deliveries, as the O'Bryant School of Mathematics & Science did this spring.
And there can be obstacles to access.
When the water supplier delivers the large bottles to the Curley School, no one is designated to carry them upstairs, so the task falls to "whoever is available," Fitch said: teachers, City Year workers, even students.
The Curley School's coolers are in cafeterias and classrooms rather than hallways, so that students from classrooms with no cooler sometimes interrupt other classes, and the cafeterias often run out of cups, Fitch said.
Richard Stutman, president of the Boston Teachers Union, said there are problems with the current system, but the lack of water fountains barely makes his list of facilities issues.
"I wouldn't put it in the top five," he said.
He said inadequate heating and cooling, outdated technology, deteriorating lavatories, and other more significant issues plague Boston's aging schools.
"The best buildings in Boston are not as good as the worst buildings in the wealthier suburbs. Period," Stutman said. "They wouldn't be tolerated for 10 seconds in Newton, Brookline, Wayland, or Weston."
But major upgrades to all Boston's schools could cost hundreds of millions of dollars, Stutman said.
"Our schools need a lot of money, and the budget just isn't there," he said. "I would argue, unfortunately, it's not there in Cincinnati, or Detroit, or Pittsburgh, or any other place in urban America. It's the shame of the country how we treat our public schools."
Richard Weir, a School Department spokesman, said the department is mindful of facilities issues and is working to ensure that they are addressed in a 10-year plan under development by the administration of Mayor Martin J. Walsh.
"The majority of our school buildings were constructed prior to the 1950s, and we recognize the need for major renovations in order to modernize these structures and better serve the educational needs of our students," he said in an e-mail.
In a statement, Walsh pledged that the plan would include bringing water fountains back to city schools.
"It is unacceptable for any student to not have access to clean drinking water," Walsh said. "That's why my 10-year master facilities plan will ensure that all schools have fountains with clean tap water."
Correspondent Monica Disare contributed to this report. Jeremy C. Fox can be reached at email@example.com. Follow him on Twitter @jeremycfox.