On average, listings lease in the $30's per square foot per year. The Brentwood region is going through a decrease in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 4% decline in rent.
In the last 90 days, 10 listings have been made available, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 10% of the office spaces in the Brentwood 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.
Even though the median size is 5,360 sqft, there are still 0 office spaces below 2,000 sqft. Most buildings in this market are approximately 3 stories. Most buildings in this market were built in 1992 and are Class A.