On average, listings lease in the $30's per square foot per year. The Brea submarket is going through a decline in rates. In the last 3 months, the median rate decreased $2 per sqft per year. That's a 5% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Brea submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 15 listings have been made available, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. About 13% of the available space in the Brea are subleases, so you might be able to find a shorter term or below market rent. 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 26,010 sqft, there are still 0 new availabilities below 2,000 sqft. Most buildings in this region are close to 2 stories. Most buildings in this area were built in 1985 and are Class B.