On average, listings lease in the $20's per square foot per year. The Hayward region is seeing a a boost in rates. In the last 3 months, the median rate increased $3 per sqft per year. That's a 12% rise in rent.
Compared to the rest of the East Bay market, the Hayward region 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 listed, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. About 27% of the available leases in the Hayward 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.
The standard measurement for office space in this area is around 1,300 sqft. Most buildings in this area are around 1 floors. Most buildings in this region were built in 1977 and are Class A.