At some point, Olympia stopped building low-density multi-family housing.
In older neighborhoods, you can find duplexes courtyard and mansion apartments dotted along blocks. Even in blocks built in the 1960s and 1970s,
you can see duplexes interspersed between single-family homes.
But as you get into newer neighborhoods, it is harder and harder to find examples of affordable, low-density multi-family housing. I can show you when this happened, but I can’t show you why.
EDIT 10:18 a.m.: Ignore that chart down below. It isn’t detailed enough. This chart really shows a population spike in Thurston County in the mid-70s and how low-density multi-family housing tracked with migration until the 1980s. Then they became untethered.
What this chart shows you is the population of Olympia by decade plotted against the construction decade of structures with two to four housing units (Use Code 12). This would cover anything from a duplex to a fourplex and some kinds of smaller apartment buildings. I think this use code is a good stand-in for what we now call the Missing Middle in Olympia.
It seems like that for most of Olympia’s history, the construction of these low-density multi-family buildings pretty much tracked with population growth in Olympia. But in the 1970s they took off, far outpacing population growth. And, then construction of these units crashed and never recovered.
Because the above data is aggregated by decade, it looks like most of the growth is happening in the 1970s. But if you look at it in more detail, you see something else happening.
It would be interesting to compare those charts with equivalent numbers in the county outside of Olympia. I suspect we'd see Olympia's restrictions of duplexes driving an increase in their construction elsewhere, encouraging sprawl.