Most listings are in the $30's per square foot per year. The Concord submarket is going through a a boost in rates. In the last 3 months, the median rate increased $5 per sqft per year. That's a 15% rise in rent.
Compared to the rest of the East Bay market, the Concord region has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 72 listings have been posted online, so you'll want to check back regularly for new listings. About 8% of the available leases in the Concord are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 3,310 sqft, there are still 0 office spaces below 2,000 sqft. Most properties in this market are around 2 stories. Most buildings in this market were built in 1984 and are Class A.