Somerville’s recent Housing Needs Assessment (HNA) is an analysis of the current state of housing in the city, and provides useful information about the types of housing Somerville needs to accommodate our changing demographics and population pressures.
Home sizes
Somerville is a city of old, large homes. 59% of occupied homes were built before 1940, while only about 9% were built from 2000 to 2020. Of all of these homes, many are large: 36% are 3 bedrooms or larger. At the same time, the average household size has decreased nationally. Even recently in Somerville, it has gone from from 2.5 people per home in 2014 to 2.36 in 2024. This chart from the HNA shows us the result: many more large homes than large households.
We have half the number of 1-bedroom and studio homes as small households. This forces smaller households to occupy larger homes which means larger households and especially families cannot occupy them. This may come as a surprise to people who note that small apartments make up the majority of new construction, but new construction makes up very little of the city’s housing stock.
A 2020 report from the MAPC concurs and shows us that regionally, many large homes are occupied by small, often older households. Somerville’s HNA has some evidence to support that happening here as well, especially since our oldest population segments are rapidly growing.
In other words, both the MAPC study and the HNA show that the region and Somerville in particular need more small homes for small households.
Building more small homes has several advantages:
It allows seniors and empty-nesters to age in community. New construction is also a great deal more accessible and easier to maintain, key considerations for seniors.
It lets 1–2 person households avoid having roommates.
Small households moving to small homes frees up large households for larger households, meaning families with children are less likely to wind up competing against groups of roommates with multiple incomes.
Household types
Everyone knows that lots of Somerville residents have roommates. The HNA’s data confirms it, showing a significant increase in the proportion of non-married households of multiple people.
While roommate households have grown, single-parent households have been driven away by the rising costs of housing and childcare. Interestingly, while the proportion of married couples has stayed steady, the number of children has drastically decreased.
Affordability
Everyone knows and feels the cost of housing here, and the HNA quantifies that by comparing tiers of household income to tiers of housing costs. Note that there are more households than apartments on both the left and right side of the chart.
This chart provides us two troubling messages. The first is that lower-income households are really hurting: nearly 20% of Somerville households are very low income, while only 10% of rentals are priced at a level that’s affordable to that income. That means a lot of people of modest means are rent burdened (defined as spending more than 30% of income on rent) or severely rent burdened (more than 50% of income). Clearly, we need a lot more subsidized housing, even though it’s enormously expensive to build and operate.
The second message is that there is room for rental costs to continue to grow. There are far more wealthy households than there are expensive apartments, which means lots of demand from people who can pay high prices.
To sop up that demand and stop it from driving up the price of existing housing, we’ll also need to allow high-end construction. Building new apartments with more amenities can draw that income segment to those homes, which leaves the rest of the homes for everyone else. And this is exactly what happened in Denver recently: their housing boom resulting in rents cooling across most of the price spectrum. New high-end construction also generates tax revenue we can use to pay for below-market affordable housing.
Despite all this interesting and rich data in the Housing Needs Assessment it lacks a clear goal of how much housing we need. For that we will look at other research next week.