On average, listings lease in the $30's per square foot per year. The Riverside region is experiencing a a boost in rates. In the last 3 months, the median rate increased $6 per sqft per year. That's a 22% rise in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Riverside submarket has less expensive rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 65 listings have been posted online, so you'll want to check back regularly for new listings. 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 2,310 sqft. Most buildings in this region are approximately 2 floors. Most buildings in this area were built in 1990 and are Class C.