Most listings are in the $30's per square foot per year. The Concord region is going through a a boost in rates. In the last 3 months, the median rate went up $5 per sqft per year. That's a 15% increase in rent.
Compared to the rest of the East Bay market, the Concord submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 72 listings have been posted online, so you'll want to check back regularly for new listings. About 7% of the available leases in the Concord are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 3,310 sqft, there are still 0 spaces below 2,000 sqft. Most properties in this market are around 2 stories. Most buildings in this market were built in 1983 and are Class A.