To preserve affordable housing along the Purple Line, Montgomery County should nearly double its housing fund to $100 million in three years, a new report says, and neighboring Prince George’s County should grow its housing fund from $6.5 million to $13 million over the same period.

The Purple Line Corridor Coalition, a group of public and private organizations in Maryland, released a 12-point “Housing Action Plan” on Thursday for how to ensure that 17,000 housing units along the 16-mile rail line remain affordable to households earning less than $70,000 annually.

“At the end of the day, we need an investment of dollars to hit these goals,” said David Bowers, vice president at Enterprise Community Partners, which co-chairs the coalition. “People shouldn’t be under the illusion that this isn’t going to need additional resources.”

In addition to the public money, the plan calls on Prince George’s to adopt stronger tenant protections and a clearer process for how to transform government-owned land and property into affordable housing — practices it says already exist in Montgomery.

The coalition’s report comes amid a growing regional push to address Washington’s affordable housing crunch, which is expected to worsen with the creation of an Amazon headquarters campus in Northern Virginia starting next year. (Amazon founder and chief executive Jeff Bezos owns The Washington Post.)

The Metropolitan Washington Council of Governments has called for 320,000 new housing units in the region between 2020 and 2030, which is 75,000 more than are currently forecast to be built. In addition, the COG says three-quarters of the new units should be affordable to low-to-moderate income earners, which means a monthly housing cost of $2,500 or less.

The Purple Line began construction in 2016 and is expected to launch operations by late 2022, with the full route opening in 2023. The light-rail route will connect working-class parts of Prince George’s with middle-income and wealthier parts of Montgomery, and could drive up property values around its 21 stations, placing small businesses and affordable housing at risk.

Of the 17,000 affordable housing units identified in the coalition report, about 6,500 are in Montgomery and 10,500 in Prince George’s.

In 2017, the two counties signed a public agreement to act against gentrification in the corridor. Last year, Maryland received a $2 million federal grant to figure out how to spur development without pricing out existing residents. And most recently, JPMorgan Chase awarded $5 million to nonprofits working to retain affordable housing and small businesses in the area.

But coalition members say those efforts are not enough — and some local officials agree.

“We need to be much more aggressive than we have in the past,” said Montgomery County Council member Hans Riemer (D-At Large), who chairs the county’s housing committee. “I’d like to see us purchase thousands of units in the Purple Line corridor.”

Montgomery County Executive Marc Elrich (D) recently broke ranks with the council and regional leaders by rejecting the affordable housing targets set by the Council of Governments and the Urban Institute. Elrich said he thought the targets for Montgomery were too high, and he pledged instead to boost incomes in the county as a way to ease the housing crunch.

But a spokesman for Elrich said Wednesday that he approves of the coalition’s proposal to increase the county’s housing fund to $100 million, and thinks it is feasible.

“We believe this is achievable in the current administration’s tenure,” said Frank Demarais, the county’s deputy housing director. He added that affordable housing is a “very high priority” going into the county’s upcoming budget cycle but declined to say what increases are expected for fiscal year 2021.

A spokesman for Prince George’s County Executive Angela D. Alsobrooks (D) said the county “will work to support the existing residents that live along the Purple Line corridor” but declined to say whether Alsobrooks will commit the county to reaching the coalition’s $13 million target.

For the current fiscal year, D.C. Mayor Muriel E. Bowser (D) expanded the city’s Housing Production Trust Fund to $130 million — a $30 million increase from the previous year.

In comparison, Montgomery’s County Council approved $63 million for the Housing Initiative Fund, $5 million more than the previous year. About 1 million people live in Montgomery, compared with about 700,000 in the District and 900,000 in Prince George’s.

Earlier this week, Montgomery’s Office of Management and Budget told legislators that the county could face a revenue shortfall of nearly $100 million in the 2021 financial year.

Bowers said the coalition understands that funding targets could be challenging given the “current budget context.” But Demarais said it is too early to say whether these revenue forecasts will affect the money available for affordable housing.

“It’s definitely going to take political will,” Bowers said. “From elected officials and from residents.”