Brookline voters this spring may be asked to increase their property taxes to support town and school operations and help pay for a high school expansion project.

The Select Board will discuss the proposed ballot questions, recommended by the town’s 2017 Override Study Committee, at a hearing Tuesday at 7 p.m. in Brookline Town Hall.

A proposed override of Proposition 2½ would permanently raise the town’s tax levy by $11.7 million over three years, starting in fiscal 2019. An alternative option calls for a $9 million increase.

The money would help cover additional staff for school and town departments, building maintenance and repair costs, and school transportation, according to the study committee.

A separate Proposition 2½ debt exclusion would help fund a proposed expansion of Brookline High School, including a new building for ninth-graders on Cypress Street near the high school campus.

“School enrollment growth has been well documented and is the driving factor in determining the need for additional revenue and school space,’’ the study committee stated in a 121-page report issued this month.

The Select Board will vote next month whether to add the override and debt exclusion questions to the May 8 ballot.

The structure of the proposed tax override — imposed over three years — is similar to the last override the town passed, in 2015, Town Administrator Melvin Kleckner said.

That year, voters backed a $7.7 million increase in the tax levy to support the schools, as well as a debt exclusion for the Devotion School project.

The new override would include money for both the town and the schools, Kleckner said, including for additional staff and new equipment.

“The enrollment issues have been pretty unprecedented,’’ Kleckner said. “I sure hope we are not in a mode of continually going to voters for an override every year, which is essentially what we are doing.’’

The School Department has identified about $3.6 million in cuts for fiscal 2019 if no override is passed, according to the report. Those cuts would include reductions in staff and programs, said Select Board chairman Neil Wishinsky.

Wishinsky said he had hoped that the town would not need to seek another override so soon after the 2015 vote. “I’m going to be taking a good, hard look at the various components with an eye to make it less impactful on our residents,’’ Wishinsky said.

At the root of the proposed Proposition 2½ override, which would be Brookline’s third in a decade, is a long-term structural budget deficit in which expenses have outpaced property tax collections, according to the study committee.

Brookline’s soaring school population has only contributed to the problem: From 2004 to 2018, enrollment grew by 29 percent, according to the committee’s report.

During the 2017-2018 school year, 7,526 students were enrolled in Brookline’s public schools, the committee said. That figure could grow to 8,200 by the 2027-2028 year, according to estimates.

The proposed high school project would include a 120,000-square-foot building at 111 Cypress St., a 75,000-square-foot wing added to the existing high school, and renovations to the Tappan Street gym and school science labs.

Estimates for the project range from $200 million to $225 million, including the cost of acquiring the Cypress Street property through eminent domain.

The Select Board approved the land-taking in January, after Town Meeting in November approved spending up to $16.4 million for the property.

The override study committee suggested ways for the town to save money and increase revenues, such as requiring employees to contribute more to health insurance, raising parking meter rates, or levying taxes on recreational marijuana and short-term rental housing like Airbnb.

Wishinsky said the town is working to bring in more money. He pointed to new commercial properties coming on line, such as Two Brookline Place, that will help take pressure off residential taxpayers. The town expects to earn about $2 million in taxes each year from the mixed-use development, he said.

“We are trying to look at other ways to grow revenue without hitting homeowners,’’ he said.

Complicating matters for an override this year are federal tax cuts supported by President Trump and passed by the Republican-controlled Congress that go into effect for the 2018 tax year.

The tax changes limited the amount of state and local taxes a filer could deduct to $10,000, and increased standard deductions for individuals and couples filing jointly.

In Brookline, the median single-family tax bill in fiscal 2017 was $11,684.

The impact of those tax changes is unknown, “but it is widely assumed that the two changes will decrease the willingness of taxpayers to increase state and local taxes,’’ the study committee reported.

Kleckner said the federal tax package “doesn’t help at all’’ as officials make the case for more money for the town and its schools.

But he doesn’t expect it to ­affect the decisions of Brookline voters regarding an override, he said.

John Hilliard can be reached at john.hilliard@globe.com.