WASHINGTON — Congress is inching toward the most significant new federal housing legislation in decades. Both the Senate and the House this year have overwhelmingly passed sweeping bills that aim to bring down the cost of housing by making it easier and less expensive to build.

Now they just need to agree about how to do that.

Though Democrats, Republicans and President Donald Trump are all on board with tackling a housing affordability crisis that has gone national in recent years, the effort is hung up on key differences in the Senate and House versions — including how much to restrict large investors from owning single-family homes.

Housing experts are excited to see the federal government finally get involved in an issue it has long ignored, though they caution that the proposed solutions are not an instant fix, especially for a state like California that has long built far fewer homes than it needs.