Congress finally acted on housing. Now the real work begins.

For years, housing affordability was a problem hiding in plain sight. Rents were climbing faster than wages. First-time buyers locked out of markets their parents once could afford. Families doubling up, moving away or simply giving up on the idea of owning a home. The numbers were damning. The causes were well understood. And yet Washington did almost nothing. That changes with the enactment of the 21st Century ROAD to Housing Act. I spent decades building multifamily housing across this country. I know what it takes to get a project off the ground—the financing, the regulatory hurdles, the workforce—and I know how much harder all of it has gotten. More than a decade ago, it was clear to me that the U.S. had stopped building enough housing for our lowest-income families and for the large generation of Millennials and younger households entering the market for the first time. The reasons are several. The Great Recession put many homebuilders out of business, housing starts slowed to a trickle and the skilled construction workforce disappeared as a result. Restrictive zoning and land-use policies have made it very difficult to build smaller starter homes as well as duplexes, triplex...