"We have a lot of ground to catch up on," said Brad Sherwood, spokesman for the Sonoma County Water Agency.
The city needs about 13 inches of rain to match 1977, the second year of one of the worst droughts in California history, he said.
Santa Rosa gets an average of 0.19 inches of rain a day in January and 0.21 inches a day in February, the third and second wettest months of the year, respectively.
December, the wettest month, totalled just 0.41 inches last year.
Virtually all of the state is in similar jeopardy, according to the U.S. Drought Monitor's report Thursday, showing that 98.6 percent of the state has an extreme to exceptional drought.
Extreme drought covers the San Francisco Bay area and extends along the coast from Humboldt County to Orange County.
For the first time in at least 14 years, the Drought Monitor map puts part of California in the exceptional drought category, a condition currently found in only four other parts of the continental United States.
A roughly 220-mile stretch of the San Joaquin Valley from Monterey to Bakersfield, covering nearly 9 percent of the state, is exceptionally dry, the map says.
Impacts of the condition include fallowing of farmland, wells running dry and little or no rangeland grasses for cattle to graze, prompting livestock sell-offs, the report says.
North Coast grape growers are bracing for substantial crop loss this year due to the drought, and state officials say the drought will likely cost farmers hundreds of millions of dollars.