When the 21st Century ROAD to Housing Act was still a work in progress, the Senate briefly inserted a ban on corporate ownership of single-family rental housing so sweeping that it might well have killed off the small but growing build-to-rent sector. 

After furious activism by the housing supply boosters, who had been the main advocates for the law's many other provisions, that investor ban was significantly pared back. 

The final version of ROAD, which became law in July, prohibits investors who own 350 single-family rental homes from buying new ones. But it also includes a long list of exemptions for large investor purchases of single-family rentals.

The primary exemptions include homes purchased as part of a build-to-rent project and dilapidated homes that the investor spends significant money renovating. 

The new restrictions go into effect this coming January. On Thursday, the Treasury Department released a proposed rule that would create definitions for terms that go undefined in the law and clarify the scope of "excepted purchases" of single-family housing that large investors can still make. 

Build-to-rent housing that large investors can still buy is defined as a new single-family home that's never been owned by an owner-occupier, is purchased within 18 months of the home receiving a certificate of occupancy, and is occupied by a renter. 

Protected "renovate-to-rent" homes are defined as homes that had major building code violations that were fixed by the large institutional buyer and for which the investor spent at least 15 percent of the home's purchase price on improvements. 

The rule also provides definitions for rental homes owned as part of a program to boost homeownership, which is another excepted purchase large institutional investors will be allowed to make. Those programs are generally defined as programs in which the renter has the right of first refusal to buy the home and where the rent receives financial support from the homeowner to purchase the home. 

Taken together, the clarified exceptions in the Treasury rule still leave a lot of room for large institutional ownership of single-family homes in keeping with the final text of the ROAD to Housing Act. They won't have to sell the homes they already own. They can still add to the supply of investor-owned rental housing through substantial rehabs and build-to-rent projects. 

Nevertheless, the Treasury rules will impose numerous paperwork burdens on investors who'll now have to track and report, for example, precisely how much money they've spent renovating a purchased rental house or else risk a huge fine. 

Large investors who purchase a single-family home in violation of ROAD are liable for a maximum civil penalty of $1 million per home purchase. 

The proposed Treasury rule highlights what a glaring exception the investor restrictions are to the overall spirit of ROAD. Through a variety of means, the law attempts to reduce the regulatory burden on new housing. Now, large investors will have to absorb significant compliance costs just to prove that they're adding new rental housing supply in precisely the right way. 

The post Under Proposed Treasury Rule, Corporate Homebuyers Who Don't Track Their Receipts Face $1 Million Fines appeared first on Reason Magazine.

Happy Tuesday, and welcome to another edition of Rent Free. This week, we're going to jump right into it with a philosophical question: What is an accessory dwelling unit anyway? 

It's a question that officials in Somerville, Massachusetts, are realizing they didn't know the answer to after learning that a state law allowing ADUs in single-family neighborhoods could also require them to approve three-story backyard mini-apartments. 

As the Boston Globe reported on Sunday, Somerville's "deep ethos in favor of new housing" is being tested by the extent of the state law. Elected officials are describing the potential for three-story ADUs as a "joke," and the area's state lawmakers, including one who voted for the state law, are demanding reforms to stop them. 

The law in question was a statewide accessory dwelling unit (ADU) legalization tucked inside a major housing package of mostly new spending programs that passed in 2024. 

The bill required municipalities to allow ADUs of either 900 square feet or half the size of the primary dwelling (whichever is smaller) anywhere single-family homes are allowed. A subsequent rule issued by state regulators also forbade localities from imposing height and bulk limits on ADUs that are stricter than the limits imposed on primary dwellings. 

That latter rule is what's causing Somerville's freakout. 

Because the town allows triple-decker apartments (a three-story triplex common in New England) in all its single-family zones, the state rule means that it must also allow ADUs to be three stories tall. 

The Globe story notes that the mini-triple-deckers could still only be 900 square feet, meaning each floor of a mini-triple-decker would have to be pretty small. Thus far, no one has proposed building an ADU tower in Somerville. 

Even so, the town is worried that someone will eventually propose one of these "out-of-scale" units that it'll have to approve. Its officials are now agitating for changes to the state law to prevent this. 

On the one hand, one can perhaps understand why Somerville officials feel blindsided. 

The text of the 2024 ADU law allows localities to set "reasonable" height and bulk limits on accessory units. It was state regulators who decided after the law's passage that requiring ADUs to be shorter than the primary unit was "unreasonable." 

On the other hand, allowing a second home on a lot to be as tall as the first house sounds "reasonable" enough. Can one complain about out-of-scale development when the new unit is the same height as an existing home and a little bit smaller?

Somerville is not the first city where people's own colloquial definition of an accessory unit as "a tiny home that doesn't bother anyone" has clashed with official regulatory definitions that allow ADUs to be a fair bit bigger. 

San Diego's ADU Bonus program once allowed a technically unlimited number of ADUs to be built on single-family parcels near transit stops. (Height and bulk regulations imposed practical limits on how many units could fit on a site.) 

That enabled developers to build what were, in effect, ADU apartment complexes on large single-family lots throughout the city. This year, the city imposed new restrictions to stop these "monster" ADU developments, including a per-lot accessory unit cap. 

The latest dust-up in Somerville, like the San Diego controversy before it, provides several lessons about the realities of housing reform. 

The first is that the definition of "accessory dwelling unit" is completely arbitrary. 

In Massachusetts, an ADU is a 900-square-foot home that can be one story or three stories, depending on the town and zoning district it's being built in. 

In Montana, it's a 1,000-square-foot unit. In California, state law can require localities to allow ADUs as large as 1,200 square feet. Under certain conditions, these ADUs can even be sold separately from the main house. 

At a certain point, an accessory dwelling unit is just a dwelling unit. A house is a house. 

The second lesson is that any ADU reform that is actually intended to produce new housing units is going to cause controversy.  

State and local laws allowing ADUs have been one of the more common forms of housing reforms to pass. 

Supply-boosters see them as a way to get a modest number of new units. Supply skeptics don't see much to object to about allowing someone to install a kitchenette and bathroom in their garage.  

If the ADU regulations don't allow much more than the garage conversion, supply-boosters will be disappointed and push for expansions of the law. California passed dozens of ADU laws before they started enabling actual units to be built. 

If an ADU law actually allows more homes, the ADUs will look like homes, and the supply skeptics will be mad. 

No amount of branding or planning will resolve the inherent conflict of some people wanting more development while others oppose it in their neighborhoods. 

Thus far, Massachusetts' ADU law has been modestly productive. The state's ADU survey reports that 2,048 ADU permits have been issued since the state law went into effect in January 2025. About half of those units are attached ADUs (think the garage with the kitchenette). 

That's a little under 10 percent of Massachusetts total housing production during that time, per the Census Bureau's building permit survey.  

At 50 units permitted, Somerville has actually approved the second most ADUs of any jurisdiction in the state. (Boston has only approved 49.) 

But now that it's facing the prospect of allowing ADUs that look like actual homes, it's starting to get cold feet about the new law. 

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Quick Links

• Speaking of Massachusetts, the town of Marblehead (of "are we kind of being pricks?" fame) has at last had its rezoning plan, which allows apartments in more districts, accepted by state officials. 
• While Spain is tightening its tenant protections and rent controls in the face of housing protests, Portugal is trying to remove regulations on its rental housing industry. Either way, housing protesters are clashing with police. 
• Single-family homebuilder confidence continues to drop. 
• The Urban Institute has a new white paper on whether data center development is coming at the expense of housing development. 
• A new report on home construction in Chicago finds that the practice of aldermanic privilege (where individual aldermen can veto projects in their district) is strangling development. 

The post ADU Nihilism appeared first on Reason Magazine.