Last month, we reported that Marin’s population grew much faster in 2013 than it had historically, up 1 percent rather than the historical average of 0.2 percent. Last week, the US Census released numbers for cities and towns, and the numbers show an equally sunny trend.

Cities and town populations grew an average of 1.1 percent in 2013 led by 1.8 percent growth in Novato, 1.2 percent in Mill Valley, and 1.1 percent in Tiburon.

2013 Population growth. Only unincoporated Marin grew slowly.

2013 Population growth. Only unincoporated Marin grew slowly.

This is on the heels of a very slow growth decade. Between 2000 and 2010, a number of towns shrank: Sausalito, Belvedere, San Anselmo, and Larkspur, along with unincorporated Marin. As you can see from the chart above, not one part of Marin shrank in the past 3 years, a marked change. Of those towns that did grow from 2000-2010, Mill Valley and Corte Madera grew faster in the past 3 years than they did that whole decade. So did Marin County as a whole.

Other towns reversed shrinking trends. Belvedere, Larkspur, San Anselmo, Sausalito, and unincoporated Marin all shrank between 2000 and 2010, and all grew over the past 3 years.

Novato stands apart from the data as by far the fastest-growing city in the county, and it is accelerating along with the rest of the county. Between 2000 and 2010, it grew an average of 0.9 percent per year, while this past year it more than doubled that rate, to 1.8 percent. It is known as the city with the cheapest housing, but much of that cost is offset by driving. The H+T affordability index puts the city as just as unaffordable as the rest of the county, and it’s not surprising. Novatoans have longer commutes than other Marinites, while its high rate of retail leakage means plenty of them are also driving far for errands.

We don’t yet know who these new residents are by city, but we do know that they aren’t births. Most of the new residents to the county at large moved here; were it not for them, we’d be shrinking rapidly.

We also know they aren’t occupying new housing. Over the past 3 years, Marin’s housing stock has been essentially stable, growing by just 0.25 percent.

This throws a wrench into the slow-growth argument against housing. Every city is growing faster than it did from 2000-2010, and this past year every city grew more than 0.8 percent. It’s not just Novato carrying the county.

It also means that, even with essentially nothing in the way of new housing, Marin is growing. Critics are right that Marin can’t solve the region’s housing crisis on its own, but it also can’t ignore the fast-brewing problems within its own borders. Rapid population growth without housing only tightens the screws.

While anti-development activists in other suburbs have proven to be reticent to allow second units, those in Marin have been veritable boosters of the idea. That opens up the potential for another 66,000 homes without altering the feel or character of host neighborhoods. We can’t ignore that potential, or the potential for proper infill housing, any longer.