PROVO — U.S. Housing and Urban Development Secretary Alphonso Jackson has commended two Provo zoning provisions as encouraging affordable-housing development.

One provision accommodates mother-in-law apartments, and the other enables customized zoning for unique development needs.

Jackson said they help avoid excessive regulations that commonly inflate housing costs.

"We know that regulatory barriers can increase housing costs by as much as 35 percent, making it impossible for many working families to live in the cities where we work," he said. "Other communities around the country can learn from Provo's efforts to open more doors for the very people who should be our neighbors."

Other communities were studying Provo even before the public accolades, said director of community development Gary McGinn. He recently fielded an inquiry from officials who were considering a similar accessory overlay zone for their city in Colorado.

Provo planners established the accessory overlay zone in 2000 to prevent single-family residential neighborhoods from morphing into multiunit rental areas.

It mandated the owners live in houses with "mother-in-law apartments," rather than renting out both the primary and accessory units.

Residents of neighborhoods around Brigham Young University campaigned for the accessory overlay ordinance, but it also roused critics. In 2001, a group of homeowners sued Provo to either overturn it or compensate their investment losses from discontinued rentals. The court ruled in the city's behalf and was upheld on appeal to the Utah Supreme Court.

An example of the customized zoning is the Provo Housing Authority's redevelopment of the former Maeser Elementary School. The housing authority will convert the building to apartments and construct single-family houses on the property.

"It's a combination of affordable rental production, historic preservation and single-family residential development — all on the same block," said Doug Carlson, director of the housing authority. "During the initial planning period, it was clear that the PRO zone was the best vehicle, the best tool to use in our request for a zoning change."