Marin County had about 113,112 housing units as of July 2025, according to the Census Bureau. About 103,000 of them are occupied, with roughly 65% owner-occupied and 35% rented.

The housing stock barely grows. Marin issued building permits for just 149 new units in all of 2025. The state’s current planning cycle requires the county and its cities to plan for at least 14,405 new units, a target far above what has actually been built.

Marin’s homes are also old. The median home was built around 1966, so much of the stock predates modern building, energy and seismic codes. Additions, conversions and unpermitted work are common, which makes accurate square footage and permit history especially important when valuing a Marin property.