The typical asking rate per listing is in the $30's per square foot per year. The Fairfax County submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 2% decline in rent.
In the last 90 days, 31 listings have been made available, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. 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 1,930 sqft. Most properties in this market are close to 5 stories. Most buildings in this area were built in 1985 and are Class B.