Most listings are in the $0's per square foot per year. The Sonoma submarket is going through a decline in rates. In the last 3 months, the median rate fell $50 per sqft per year. That's a 100% decrease in rent.
In the last 90 days, 6 listings have been listed, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 4,640 sqft, there are still 0 office spaces below 2,000 sqft. Most buildings in this area are close to 2 floors. Most buildings in this area were built in 1978 and are Class C.