For decades, the tax code has been filled with rewards for homeownership. Tax breaks encourage people to get into first homes and to trade up as they get older, building a national mind-set that you’re never quite middle class until you’ve qualified for a mortgage.

It amounts to a vast social engineering project that assumes society is better off with owners instead of renters. But the tax bill making its way toward final passage is upending that premise.

The bill will increase many homeowners’ monthly housing costs by scaling back deductions that allow them to reduce mortgage interest and property taxes. And by roughly doubling the standard deduction, it reduces the incentive to buy homes by making far fewer homeowners eligible for preferential tax treatment.

Today, a little under half of American homes are worth enough to justify itemizing mortgage interest and property taxes. Under the tax legislation, that figure would fall to close to 14 percent, according to an analysis of the plan by the online real estate marketplace Zillow.