Signs warning students not to drink the water have long served as a grim reminder about the reality of Baltimore school buildings’ conditions. The majority of schools in the city have relied on bottled water for a decade, following revelations about lead contamination that forced officials to ban drinking out of water fountains or sinks.

But with new and renovated buildings rapidly opening and a pilot program underway, more than two dozen schools this year are allowing students and teachers to drink from fountains they say are safe to use.

That still leaves most of the district’s roughly 170 schools relying on jugs of bottled water for drinking and cooking — a solution that’s cost the district millions over the years.

There are 16 Baltimore schools equipped with systems that make all the water safe to drink:

Academy for College and Career Exploration

Arundel Elementary School

Carver Vocational-Technical High School

Cherry Hill Elementary/Middle School

Dorothy I. Height Elementary School

Forest Park High School

Fort Worthington Elementary/Middle School

Frederick Elementary School

Highlandtown Elementary/Middle School 237

Independence School Local I

Leith Walk Elementary/Middle School

Paul Laurence Dunbar High School

Pimlico Elementary/Middle School

Violetville Elementary/Middle School

Waverly Elementary/Middle School

Wildwood Elementary/Middle School

The majority of those schools were recently rebuilt or renovated under the 21st Century School Buildings Program, a $1 billion initiative established in 2013 by the Maryland General Assembly in partnership with the city, the Maryland Stadium Authority, the city school system and the state’s Interagency Committee on School Construction.

Five new buildings opened this school year: Pimlico, Forest Park, Arundel, Cherry Hill and the Robert Poole Building, home to the Academy for College and Career Exploration and Independence.

The program will eventually bring up to 28 modernized school buildings to Baltimore, which is home to the state’s oldest education infrastructure. The new buildings are equipped not only with drinkable water, but air-conditioning and heating.

Three additional schools — Hampstead Hill Academy, Lakeland Elementary/Middle and Yorkwood Elementary — are outfitted with lead removal filters on specific water fountains.

Hampstead Hill, a public charter school, has used these filters for years with good results. The other two schools are part of a pilot program to test the system. The pilot was also rolled out at the district’s headquarters on North Avenue.

The system being tested was developed by EcoWater Systems LLC in Minnesota to filter lead and other impurities out of the water. The filters are certified by NSF International, a nonprofit that checks devices used to protect food and water.

If the filters continue to work as planned, the district will seek bids to install the systems across the rest of its buildings.

“The pilot is ongoing, and the district will evaluate the results to inform potential expansion at the end of the 2018-19 school year,” city schools spokeswoman Anne Fullerton wrote in an email Thursday.

There are also eight charter and contract schools with water filtration systems. These schools are housed in buildings not owned by the district.

The schools are: Afya Public Charter, Tunbridge Public Charter School, City Neighbors Charter, Coppin Academy, Elmer A. Henderson: A Johns Hopkins Partnership School, The Green School of Baltimore, Green Street Academy and Monarch Academy.

— Talia Richman