Most listings are in the $20's per square foot per year. The Kennewick region is seeing a a rise in rates. In the last 3 months, the median rate went up $10 per sqft per year. That's a 60% rise in rent.
In the last 90 days, 11 listings have been made available, which means spaces most likley are going fast. You'll want to be prepared to make an offer immediately. About 9% of the available space in the Kennewick are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,900 sqft. Most buildings in this market are approximately 2 floors. Most buildings in this region were built in 2003 and are Class B.