Most listings are in the $20's per square foot per year. The Fountain Valley submarket is experiencing a a boost in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 7% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Fountain Valley submarket has lower rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 28 listings have been posted online, which means leases might be going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,000 sqft. Most properties in this area are around 3 floors. Most buildings in this market were built in 1982 and are Class B.