Most listings are in the $20's per square foot per year. The Washington submarket is going through a an increase in rates. In the last 3 months, the median rate went up $3 per sqft per year. That's a 13% rise in rent.
In the last 90 days, 963 listings have been made available, so you'll want to check back regularly for new listings. About 110% of the available leases in the Washington are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 2,340 sqft. Most properties in this area are approximately 2 stories. Most buildings in this area were built in 1984 and are Class A.