Housing Developer Math

I’ve had an annual ritual for the past several years: obtain a spreadsheet of property assessments from the Town Assessor, load them in to a database, and run a series of R computations against the data. I started doing this for a number of reasons: to understand what was built where (our zoning laws have changed over time, and there are numerous non-conforming uses), the relationship between land and building values, the capital costs of different types of housing, and how these factors have changed over time.

I’d typically compile these analyses into a fact-book of sorts, and email it around to people that I thought might be interested. This year, I’m going to post the analyses here as a series of articles. This first installment contains basic information about Arlington’s low-density housing: single-, two-, and three-family homes, as well as condominiums. Condominiums are something of an oddball in this category — a condominium can be half of a two-family structure, part of a larger residential building, or somewhere in between. There’s a lot of variety.

Here’s a table showing how the number of units has changed over time, since 2013.

Arlington’s predominant form of housing — the single family home — has stayed relatively static; we’ve added 15 over the last seven years. The number of condominiums has increased significantly: +585 over seven years. That, coupled with the reduction of two-family homes (-213) and three-family homes (-25) leads me to believe that a fair number of rental units have been removed from the market.

Next, I’d like to look at how these homes are spread across our various zoning districts. (The “Notes” section at the bottom of the post explains what the zoning district codes mean).

A few points to note:

• R0 is our newest district, which was established in 1991. It consists only of conforming single-family homes.
• R1 is Arlington’s original (per 1975 zoning) single-family district. It’s predominantly single-family homes, but there are a fair number of two-family homes, and even a few three-families. The presence of condominiums suggests additional multi-family homes (that consist of two or more condominiums)
• R2 is predominantly two-, and three-family homes. Although three-family homes are no longer allowed in this district, R2 has the largest number of three-families in town.
• Residential uses are no longer allowed in the industrial (I) districts, but the I districts contain 34 homes. These buildings pre-date the current zoning laws (aka “pre-existing non-conforming”). A good portion of the Dudley street industrial district is a residential neighborhood.

I’m pointing out these conformities (and non-conformities) for a reason. The zoning map (and use tables) dictate what is allowed today, along with specifying a vision for the future. Our zoning bylaw happens to contain a strong statement to this effect: “It is the purpose of this Bylaw to discourage the perpetuity of nonconforming uses and structures whenever possible” (section 8.1.1(A)). Despite the strong statement of intent, it can take decades (if not generations) for a built environment to catch up with the bylaw’s prescriptions.

I’ll finish this post with a breakdown of how condominiums are distributed across the various zoning districts:

The last column (“delta”) shows the difference between 2013 and 2020. The largest increase occurred in the R2 (two-family) district, followed by R6 (medium-density apartments, where most of the increase took place in 2014) and R1 (single-family).

That it will do it for the first installation. In the next post, we’ll look at how the cost (assessed values, actually) of Arlington’s low density housing has changed over the last seven years.

Here is a spreadsheet, containing the various tables shown in this article.

Notes

Arlington’s zoning map divides the town into a set of districts, and each district has regulations about what kinds of buildings and uses are allowed (or not allowed). The districts mentioned in this article are:

• B1 (Neighborhood Office district)
• B2 (Neighborhood Business distrct)
• B2A (Major Business District)
• B3 (Village Business District)
• B4 (Vehicular-Oriented Business District)
• I (Industrial District)
• R0 (Single-Family, large-lot district)
• R1 (Single-Family Distict)
• R2 (Two-Family District)
• R3 (Three-Family District)
• R4 (Townhouse District)
• R5 (Low-Density Apartment District)
• R6 (Medium-Density Apartment District)
• R7 (High-Density Apartment District)

Arlington’s Zoning Bylaw describes each district in detail (see sections 5.4.2, 5.5.2, and 5.6.2)