On average, listings lease in the $10's per square foot per year. The Ukiah region is going through a a boost in rates. In the last 3 months, the median rate increased $19 per sqft per year.
In the last 90 days, 1 listings have been listed, which means spaces might be going fast. You'll want to be prepared to make an offer immediately. 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 1,550 sqft. Most buildings in this market are close to 1 stories.