On average, listings lease in the $30's per square foot per year. The Chantilly submarket is going through a an increase in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 5% rise in rent.
Compared to the rest of the Washington D.C. market, the Chantilly region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 79 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the listings in the Chantilly are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 11,702 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this region are close to 2 stories. Most buildings in this market were built in 1997 and are Class A.