The assessed value of Napa County property increased by $2.4 billion for the 2017-18 tax year, the largest dollar increase in county history, Assessor John Tuteur told the Napa County Board of Supervisors Tuesday morning.

“We grew more in one year than was the entire value of the roll 37 years ago,” Tuteur reported.

The current value is $37.426 billion. Back in 1980, the entire value of the Napa County tax roll was $2.37 billion, Tuteur said.

“Our $37.426 billion local roll is the third highest per capita assessed value of California’s 58 counties, just behind Marin and San Mateo and just ahead of San Francisco,“ Tuteur said.

The 2017-18 roll was up 6.88 percent, reflecting rising home values and significant non-residential construction, supervisors were told.

Approximately $500 million of the $2.4 billion increase comes from the Proposition 13-required inflationary increase not to exceed 2 percent on properties that did not change ownership, had no new construction and were not in a decline-in-value status.

Another approximately $207 million represents continued upward adjustment of properties that were in a decline in value status due to the impact of the Great Recession on real estate, Tuteur said.

Non-residential new construction added $238.4 million in assessed value — the third largest increase since 1990.

The balance of the 6.88 percent increase comes from changes of ownership of properties with older Proposition 13 base year values and residential new construction.

Every municipality showed an increase in their assessed values, which provide property tax revenue:

—American Canyon, 6.04 percent;

—Calistoga, 9.58 percent;

—-the City of Napa, 6.29 percent;

—Saint Helena, 6.56 percent;

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—Yountville 20.69 percent.

Yountville’s sizable increase was tied to the sale of several major commercial properties within the town limits, Tuteur said.

The effects of the Great Recession, which caused home values to tumble, remain. The number of properties in a decline-in-value status dropped from 4,430 in 2016-2017 to 3,763 as of Jan. 1.

The aggregate decline in value of these 3,763 properties is almost $700 million below their Proposition 13-factored base year value. “These upward adjustments were based on real estate market data showing that the recovery remained steady during calendar year 2016,” Tuteur said.

Online value notices are now available to property owners in a decline in value status and also for properties with business and farm equipment assessments; agricultural properties under California Land Conservation (Williamson Act) contracts and properties that had construction in progress between Jan. 1, 2016 and Dec. 31, 2016.

Notices can be searched by either assessor parcel number or property address at

“I encourage property owners to compare their 2017-2018 value notices to their 2016-2017 property tax bills to understand the nature of the change,” Tuteur said in a news release.

“For those who have questions about the value shown on their notice please call or e-mail the assessor division for an informal review prior to Nov. 15,” he said. “Our staff is available to answer any questions at (707) 253-4459 or