The typical asking rate per listing is in the $10's per square foot per year. The Dumbarton submarket is going through a an increase in rates. In the last 3 months, the median rate rose $18 per sqft per year.
In the last 90 days, 7 listings have been made available, which means spaces most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 43% of the available leases in the Dumbarton are subleases, so you might be able to find a shorter term or below market rent. 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 19,310 sqft, there are still 0 office spaces below 2,000 sqft. Most buildings in this area are around 1 stories. Most buildings in this area were built in 1989 and are Class A.