On average, listings lease in the $10's per square foot per year. The Antioch submarket is going through a decline in rates. In the last 3 months, the median rate decreased $10 per sqft per year. That's a 33% decrease in rent.
Compared to the rest of the East Bay market, the Antioch region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 14 listings have been posted online, which means new availabilities might be leasing quickly. You'll want to be prepared to make an offer immediately. 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 2,000 sqft. Most buildings in this region are around 1 floors. Most buildings in this area were built in 1989 and are Class C.