In the last 90 days, 13 listings have been posted online, which means new availabilities most likley are going fast. You'll want to be prepared to make an offer immediately. About 8% of the available space in the Fountain Valley 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.
The standard measurement for office space in this area is around sqft. Most buildings in this area are approximately 3 floors. Most buildings in this area were built in 1982 and are Class B.