Most listings are in the $20's per square foot per year. The Hayward region is going through a decrease in rates. In the last 3 months, the median rate fell $2 per sqft per year. That's a 10% decline in rent.
Compared to the rest of the East Bay market, the Hayward submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 15 listings have been made available, which means new availabilities are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 7% of the available leases in the Hayward 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.
Even though the median size is 6,190 sqft, there are still 0 office spaces below 2,000 sqft. Most buildings in this area are approximately 1 floors. Most buildings in this market were built in 1981 and are Class A.