Most listings are in the $20's per square foot per year. The Brentwood submarket is seeing a a rise in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 4% increase in rent.
Compared to the rest of the East Bay market, the Brentwood submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 12 listings have been posted online, which means new availabilities might be going fast. You'll want to be prepared to make an offer immediately. About 8% of the listings in the Brentwood are subleases, so you will probably have to focus your search on direct office leases. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,990 sqft. Most properties in this region are approximately 1 stories. Most buildings in this region were built in 2003 and are Class A.