On average, listings lease in the $30's per square foot per year. The Brentwood submarket is going through a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 4% decrease in rent.
In the last 90 days, 7 listings have been posted online, which means office spaces most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 429% of the available space in the Brentwood 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 on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,100 sqft. Most properties in this region are around 3 stories. Most buildings in this region were built in 1994 and are Class A.