Most listings are in the $30's per square foot per year. The West Covina submarket is seeing a decline in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 8% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the West Covina submarket has greater rates, and you'll need to pay a premium to be in this hot submarket.
In the last 90 days, 22 listings have been listed, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 5% of the listings in the West Covina are subleases, so you will probably have to focus your search on direct office leases. 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 1,790 sqft. Most buildings in this market are around 2 stories. Most buildings in this market were built in 1980 and are Class B.