"I'm not so sure I've seen such a significant impact in one year from a single company, ever," Stone said Monday.
Driving the increase is a massive purchase of office equipment and furniture by Google — to the tune of nearly a half-billion dollars.
The resulting increase in Google's overall assessed value makes it the second-largest company in the county, behind Cisco, said David Ginsborg, spokesperson for the assessor. Last year it was the third largest.
Stone says that for the first time since 2008, nearly every city in the county is seeing an increase in property tax revenue in this latest assessment roll, "the first concrete evidence that the Silicon Valley economy is finally heading in a positive direction," Stone said in a press release.
Mountain View's tax roll growth is the largest among the county's cities, growing by 6.56 percent over the year, while the county overall increased 3.25 percent. The next highest tax roll growth came from Cupertino, at 6.35 percent, and Santa Clara, with 6.15 percent. Palo Alto had 5.32 percent growth.
In Mountain View the increase can be attributed to a 30.3 percent rise in "unsecured" or business personal property values, such as major purchases of machinery, equipment, computers and fixtures by companies. Cupertino and Santa Clara also saw big increases, while Palo Alto saw a 10 percent decrease. "That's all furnishing in big buildings," said Ginsborg, of the assessor's office.
"The growth of business property is perhaps the best indicator that businesses are once again hiring new employees, leasing office space, and making major purchases," Stone said.
And 80 percent of the unsecured property tax growth in Mountain View is from Google, Ginsborg said. The value of the company's unsecured property went from $652 million to $1.1 billion over the last year.
"It's very impressive, the kind of impact a single company can have," Stone said. "It's very much like the impact Apple had on Cupertino a decade or so ago and probably what Hewlett-Packard had on Palo Alto a couple decades or so ago."
But while tech companies may be growing like crazy, the economy hasn't lifted residential values to the same degree. There was an increase in Mountain View single-family home values of 5 percent, but 20 percent of homes in Mountain View saw a decrease in value," Ginsborg said. In the county overall, 27 percent of homes were devalued.
"Things happen in Silicon Valley first and fastest, good and bad," Stone said. "You are seeing the good part of it. And it goes down very rapidly. The dot-com bust had a significant impact on Silicon Valley all at once. We're essentially a one-industry region."