The typical asking rate per listing is in the $20's per square foot per year. The Cascades submarket is going through a a boost in rates. In the last 3 months, the median rate increased $24 per sqft per year.
Compared to the rest of the Washington D.C. market, the Cascades region has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 3 listings have been made available, which means new 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,770 sqft. Most properties in this area are around 3 stories. Most buildings in this region were built in 2001 and are Class B.