These maps show why some California Republicans are nervous about changes to the tax code

California taxpayers would be hit disproportionately hard under the Republican tax plan because of changes to two popular tax breaks.

That's one reason GOP lawmakers in the state's House delegation were under so much scrutiny when most of them voted to pass the House version in November. Several members said they agreed to move the bill forward with the promise of a fix later.

The House proposal would eliminate much of the state and local tax deduction, known as SALT, and set a limit of $500,000 on the mortgage debt that can be used to claim the mortgage interest deduction. The current Senate proposal eliminates the SALT deduction entirely, but keeps the mortgage interest deduction at $1 million.

As Senate and House leaders negotiate a final package, House leaders are considering keeping a version of the deductions in order to get the state’s Republican members on board for a final vote.

We took a look at the 14 California congressional districts represented by Republicans and calculated the share of residents who take the SALT deduction and the percentage of new mortgages over $500,000 in 2017. Many of them match up with the districts Democrats hope to win in their bid to retake control of the House, according to a Times analysis of data provided by CoreLogic and the IRS.

Democrats intend to use the tax vote against Republicans who represent districts that will be battlegrounds in the midterm elections next fall.

Times staff writer Sarah D. Wire contributed to this report.

Sources: Times reporting, media reports, CoreLogic, Internal Revenue Service, U.S. Census Bureau, OpenStreetMap