Editor's Note: This article was updated on Dec. 20.

The first tax system overhaul in over three decades is expected to head to President Donald Trump’s desk today.

Senate Republicans passed the much-anticipated tax measure early Wednesday morning on party lines, 51-48. The House of Representatives passed the bill on Tuesday afternoon on party lines, with 227 Republicans voting for it and 12 Republicans and all Democrats opposing it. The House also had to revote on Wednesday morning after the Senate parliamentarian ruled several provisions out of order, with the same votes as the day before.

After a roller-coaster ride for the affordable housing industry this fall, leaders breathed a sigh of relief Friday when the tax reform bill was released after conference committee negotiations. Both low-income housing tax credits (LIHTCs) and private-activity bonds (PABs) have been preserved in the bill.

“While we didn’t get everything we wanted, and whoever does, we’re whole,” says David Gasson, executive director of the Housing Advisory Group and vice president at Boston Capital.

Bob Moss, principal and national director of governmental affairs at CohnReznick, says the inclusion of LIHTCs and PABs has been a team effort on part of the industry.

“You can never underestimate grassroots support and advocacy,” he says.

According to an analysis by accounting firm Novogradac & Co., the final version of the legislation would reduce the future supply of affordable rental housing by nearly 235,000 homes over a decade. This analysis is based on the corporate rate being reduced from 35% to 21%, a move that could diminish the value of the housing credit for investors and reduce investment in housing credits, and the change in inflation adjustments throughout the tax code from a factor based on the consumer price index for all urban consumers (CPI-U) to one based on a “chained” CPI-U, according to Novogradac.

"The Tax Cuts and Jobs Act will decrease affordable housing production as a result of the lower corporate rate and other provisions—continuing a trend that we have already seen for the past year in anticipation of tax reform," says Emily Cadik, director of public policy at Enterprise Community Partners. "However, the fact that the LIHTC and multifamily housing bonds were retained in the tax code is still a major victory for the affordable housing industry, since both programs faced risks in tax reform as the GOP looked for tax expenditures to eliminate to fit inside their budgetary constraints."

Housing advocates also are still trying to get a better understanding of the effects of the Base Erosion and Anti-Abuse Tax (BEAT) provision that could put some tax credit investors with foreign parent organizations or U.S.-based investors with significant foreign operations out of the market. The final bill mitigated industry concerns by allowing 80% of the housing credit to be used against the BEAT, but uncertainty remains.

"We are afraid that housing credit investors will find out in the coming weeks that they are subject to this new BEAT," says Peter Lawrence, director of public policy and government relations at Novogradac. "They'll lose 20% of the value, and that may be enough to put some investors out of the market. That's very concerning."

Other positive news for the affordable housing industry includes retaining the New Markets Tax Credit through 2019. On historic tax credits, the bill eliminates the 10% non-historic credit, and the 20% credit would be taken over five years.

What's next

Industry leaders believe there will be an adjustment period, but the market will find its footing at the lower corporate rate. It also will continue its advocacy work to keep the LIHTC program whole.

"The industry will now seek modifications to the housing credit to ensure we continue to produce at least as much affordable housing as we did prior to tax reform," says Cadik. "We are also going to keep working to advance the Affordable Housing Credit Improvement Act (S. 548 and H.R. 1661) introduced by Sens. Maria Cantwell (D-Wash.) and Orrin Hatch (R-Utah) and Reps. Pat Tiberi (R-Ohio) and Richard Neal (D-Mass.), which we will need now more than ever. The preservation of the housing credit and housing bonds in tax reform demonstrated yet again that we have many affordable housing supporters on both sides of the aisle, which will provide a strong foundation for these ongoing efforts."

Lawrence adds that Congress also is expected to do a technical corrections bill at a later date. "The speed at which this bill was rushed through Congress and the unintended consequences of many of the provisions will become more and more apparent over time. The BEAT is just one example of countless others in the legislation. Already there is some talk of a corrections bill."

Moss and Lawrence also point to the Trump administration's push for an infrastructure bill in 2018 as a possible vehicle for tax provisions.

"Affordable housing is infrastructure," notes Lawrence.