On average, listings lease in the $40's per square foot per year. The Somerville region is going through a an increase in rates. In the last 3 months, the median rate went up $4 per sqft per year. That's a 10% rise in rent.
Compared to the rest of the Greater Boston market, the Somerville region has higher rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 34 listings have been made available, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,100 sqft. Most properties in this area are close to 4 stories. Most buildings in this region were built in 1989 and are Class B.