On average, listings lease in the $20's per square foot per year. The Santa Rosa region is experiencing a a rise in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 3% rise in rent.
Compared to the rest of the Bay Area market, the Santa Rosa submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 33 listings have been posted online, which means new availabilities might be going fast. You'll want to be prepared to tour spaces as quick as possible. About 3% of the available space in the Santa Rosa are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,240 sqft. Most buildings in this region are approximately 2 floors. Most buildings in this area were built in 1982 and are Class B.