The district was tipped off after its companion district in Placer County found an Aedes aegypti mosquito nearby.
A door to door canvas uncovered a Zika mosquito in a backyard watering can along with larvae and eggs.
More were found when traps were put out.
The spraying took place over a half-mile radius. The district says the quick action is warranted, even though the mosquitos showed no signs of the Zika virus, which garnered worldwide attention a few years ago when it was found to cause birth defects among infected pregnant women.
"We acted immediately to make sure that we're deploying all of our staff and resources to get a handle on the situation," said district spokesperson Luz Maria Robles.
The mosquito can also transmit the even more dangerous dengue fever and chikungunya viruses, usually from travelers to tropical countries who return home.
Previously, the non-native species was found only as far north as Fresno, but this year made its way to the Modesto area in San Joaquin County. Citrus Heights and the South Placer County area is the farthest north it's been detected so far.
The district says it is an aggressive day time feeder and that it wants people who have been bitten by mosquitos during the day to call them.
More common species feed during dawn and dusk.
Along with the daytime spraying, crews will use trucks after sundown to spray along streets in the area.