Most listings are in the $10's per square foot per year. The Watertown submarket is seeing a a rise in rates. In the last 3 months, the median rate rose $16 per sqft per year. That's a Inf% rise in rent.
In the last 90 days, 8 listings have been made available, which means spaces 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,200 sqft. Most properties in this area are approximately 2 floors. Most buildings in this market were built in 1924.