Cambridge, Massachusetts, requires that 20% of the new space in larger housing developments include affordable homes. This, as we have talked about many times before on this blog, is known as inclusionary zoning (IZ). According to the Pioneer Institute, there are more than 141 communities in the state that have some sort of IZ policy.

But now, what is happening is that the numbers don't work on new housing projects. In the 30 years since the ordinance was enacted, it is reported that it helped create 1,603 affordable homes. However, since 2017 — the year the city increased the affordable requirement to 20% — only 200 new affordable homes have been created. That's approximately 20-22 new affordable homes per year — not much.

These numbers also don't speak to the number of new housing projects that could have been built, but weren't feasible precisely because of the IZ policy. This is the greater risk, because even new "luxury" projects help to relieve housing pressures within a market.

It is for this reason, along with others, I'm sure, that a developer is now suing the City of Cambridge, arguing that inclusionary zoning is unconstitutional on the grounds that it infringes upon people's property rights. To quote the developer, "I [would] have to build at a loss. Eventually, you just throw your hands up and say it doesn't work."

If successful, this case could help to change how cities tax new housing and how they aim to create new affordable housing, though I should mention that there have already been prior rulings on this issue.

Customarily, the way municipalities try to offset the burden of inclusionary zoning is to allow additional density and/or waive certain development levies. However, to accomplish this, you ideally need a planning framework where it's perfectly clear what maximum density would have been permitted without IZ.

For example, if 100,000 square feet is the maximum permitted density without IZ, and an additional 20% is permitted with IZ (+20,000 square feet) you can now calculate whether this additional density is enough to perfectly offset the IZ tax. If it is not, well then, you could maybe have a situation where it's deemed as an unconstitutional "taking" of private land (oh boy, please don't take this as any sort of planning legal advice).

I think most of us would agree that cities are better when they are diverse and attainable to more people. The problem with IZ policies is that they run the risk of selectively taxing only certain people in an effort to create this outcome.

Cover photo by Brett Wharton on Unsplash

One of the common criticisms of new housing is that it's designed for rich people and that it does nothing to help the housing situation of average citizens. The YIMBY response to this is, "Well, yes, it does actually, because supply eases overall housing pressures and because of the filtering effect." This is the process whereby housing becomes gradually more affordable and available to people as new housing is built and vacancies are created. But most people don't like this explanation. It feels slow and indirect.

Here's something that might help.

In this recent study, researchers looked at the downstream effects of a new condominium tower in Honolulu called The Central Ala Moana. Completed in 2021, the building contains 512 units, of which 60% are income-restricted (310 units) and 40% are market-rate (202 units). It was developed under a state affordable-housing program that gave the developer height and density bonuses, plus fee waivers totalling about $13 million in exchange for delivering income-restricted units. (In my opinion, this is directionally preferable to unfunded inclusionary zoning mandates.)

Using address-history microdata, the researchers tracked who moved into the new condominium tower, and constructed detailed vacancy chains across multiple rounds of moves. Here's what they discovered:

Among documented vacancies, the 202 market-rate units produced 87 downstream vacancies (0.43 vacancies per initial unit), while the 310 income-restricted units produced 90 (0.29 vacancies per unit). Thus, market-rate units are more likely to generate a downstream vacancy. The main mechanism is new household formation: movers into income-restricted units are more likely to be a newly formed household, leaving family or roommates at the prior address and thus preventing a vacancy from being created.

In absolute numbers, they found that the completion of the building induced more than 500 local vacancies in the three years after construction, by setting off a chain of moves. Importantly, the researchers also found that the homes being vacated were, on average, about 40% less expensive than those in The Central. So even though a new building may be more expensive than the existing housing stock (which is generally the case or else the development wouldn't happen), it does generate benefits.

It eases overall housing supply constraints and expands affordability in the local housing market.

Cover photo by Michael Olsen on Unsplash

The vast majority of new purpose-built rental housing in Canada relies on CMHC-insured loans to make them financially feasible. In 2024, CMHC estimated that their construction financing programs backed an estimated 88% of new rental starts across the country.

But anyone in the industry will tell you that the terms in which these loans are made available to developers are constantly changing. And I think it's pretty clear that many of the changes being made are intended to push, maybe force, developers into building some percentage of affordable homes as part of their projects.

At the political narrative level, this makes sense: Canada needs more affordable housing. But it's important to remember that homes pegged to below-market rents are not financially feasible to build on their own. So, unless equivalent subsidies are being somehow provided, the remaining market-rate homes will be forced to shoulder the additional costs.

We talk about this a lot on the blog (see inclusionary zoning posts), and I don't see it as an equitable solution. But there's also the problem of it further choking off new housing supply. And my sense is that that's exactly what is happening. It's only getting harder to underwrite new rental housing — certainly in cities like Toronto.

This will have the opposite effect on overall affordability. It also increases the probability that my supply predictions will prove roughly correct. I can't see a world where new rental supply is able to step up and fill the gap being left by new condominiums, a large portion of which was serving as new rental housing.

Toronto is on a path toward a severe housing shortage, and it's very hard for the private sector to do much about it in the current market environment. When that will change remains to be seen.

Cover photo by Darren Richardson on Unsplash