Ask an economist how to make housing more affordable in the U.S. and they'll likely mention a straightforward solution: build more homes.
While it's not a silver bullet, building more homes gives buyers and renters more options, helping slow the upward climb of home prices and rents. It can even lower prices if a market is experiencing significant overbuilding.
In Pennsylvania, those dynamics sit at the heart of two bipartisan bills that state lawmakers hope to pass this session as part of a broader housing push. Both look to increase the state's supply of so-called accessory dwelling units, or ADUs, independent dwellings that are attached to a single-family home or sit separately on the property.
The bills would require municipalities to allow them by right, meaning property owners wouldn't need discretionary approval to build them, even if they are restricted locally by their municipality.
In many municipalities around the state, building an ADU requires a zoning variance — approval to deviate from the law. Advocates say that often creates a time-consuming and expensive impediment to building, whether a homeowner wants to build a tiny home, convert a garage or create a basement apartment.
The bills in Harrisburg would effectively bypass that approval process by creating a statewide standard for ADUs, increasing the certainty that homeowners can make these projects happen.
"The current systems in place have gotten us into this situation, and so we need to try to do things. We need to change and adapt," said state Rep. John Inglis, D-Allegheny, who introduced the House version of the measure.
Local governments are opposed
The effort comes amid a statewide housing crisis partly shaped by a shortage of units, especially affordable rentals for low-income residents. At the current "build rate," Pennsylvania will be short roughly 185,000 homes by 2035, according to the Shapiro administration's housing plan.
Proponents say ADUs can help close the gap, while providing homeowners with additional income and tenants with more independence. They are typically small rentals and are considered an example of "gentle density" along with duplexes, triplexes and multiplexes.
"I don't think there is a game-changing policy step that could be taken to change things quickly next month or even next year. But all these steps to increase available supply are very positive and directionally very important," said Mark Zandi, chief economist at Moody's Analytics.
Opponents strongly disagree. Organizations representing local governments call the bills a "one-size-fits-all mandate" that discounts the land-use expertise of municipalities across the state, a move they say will create "real challenges."
"These challenges include exceeding street parking capacity; exceeding water, sewer, and storm water infrastructure capacity; hindering emergency services access to dwellings and ADUs; and further increasing density in already dense neighborhoods," the Pennsylvania Municipal League and the Pennsylvania State Association of Township Commissioners said in a joint statement.
The bills in the House and Senate are similar to measures passed in several states, including California, Massachusetts and Oregon. And while they mirror one another, they are not carbon copies.
In the House, the measure permits ADUs by right on a "parcel or lot on which a residential building is present or may be constructed," while the Senate version applies more narrowly to land where a single-family home sits or can be built.
Will these bills be passed?
For now, the Senate bill also doesn't apply to Philadelphia and Pittsburgh, though amendments could be added to change that. The House measure, which has passed the chamber, would apply to every municipality in Pennsylvania.
State Sen. Nikil Saval, D-Philadelphia, said either bill would be a boon for Pennsylvania households, more than 1 million of which are considered cost-burdened, according to Gov. Josh Shapiro's plan. That means that more than 30% of their monthly income goes towards housing costs.
"While there has been pushback, we know that a majority of people support this, a majority of people want to be able to build housing on their property. They want to be able to make it easier for their communities to grow. And actually enabling their communities to grow is the way that we preserve them. It's a way that we preserve affordability or increase affordability," said Saval, who co-sponsored the bill.
The Senate bill is currently stalled. State Sen. Joe Picozzi, majority chair of the chamber's urban affairs and housing committee, has yet to take action on the legislation. He did not respond to multiple requests for comment.
The committee has met only twice this year.
Mario Mascioli, owner of Acorn Built Homes, is closely watching the legislative process. His firm specializes in accessory dwelling units, and he said his company is inundated with calls from residents wanting to build one on their property.
To him, passing an ADU measure in Pennsylvania is "mission critical" to solving the state's affordable housing crisis.
"The primary drivers are true here and everywhere else. Aging in place, the No. 1 driver. Second driver is adult children that can't afford rent or certainly to buy a home. Third is a need for more income, rental income," said Mascioli, whose company serves the Philadelphia suburbs.
Shapiro is expected to sign any measure designed to expand the creation of ADUs in Pennsylvania.
In his administration's housing plan, he points to these homes as a way of expanding housing opportunities in the state, saying homeowners should have the chance to "build new structures and renovate underutilized structures into accessory dwelling units."
The final day of the current session is Nov. 30.