| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 108 | 1 | 1 | 100% |
| Alpine | - | - | - | - |
| Amador | 4 | - | - | - |
| Butte | 7 | - | - | - |
| Calaveras | 1 | - | - | - |
| Colusa | 1 | - | - | - |
| Contra Costa | 102 | 5 | - | - |
| Del Norte | 2 | - | - | - |
| El Dorado | 8 | 3 | - | - |
| Fresno | 37 | 1 | 1 | 100% |
| Glenn | - | - | - | - |
| Humboldt | - | - | - | - |
| Imperial | - | - | - | - |
| Inyo | 1 | - | - | - |
| Kern | 7 | - | - | - |
| Kings | 6 | - | - | - |
| Lake | 2 | - | - | - |
| Lassen | - | - | - | - |
| Los Angeles | 275 | 11 | - | - |
| Madera | 2 | - | - | - |
| Marin | 16 | - | - | - |
| Mariposa | 1 | - | - | - |
| Mendocino | 2 | - | - | - |
| Merced | 5 | - | - | - |
| Modoc | - | - | - | - |
| Mono | - | - | - | - |
| Monterey | 32 | 1 | - | - |
| Napa | 8 | 2 | - | - |
| Nevada | 4 | 1 | - | - |
| Orange | 107 | 21 | - | - |
| Placer | 33 | - | - | - |
| Plumas | - | - | - | - |
| Riverside | 49 | 5 | - | - |
| Sacramento | 186 | 38 | - | - |
| San Benito | 1 | - | - | - |
| San Bernardino | 32 | 3 | - | - |
| San Diego | 149 | 29 | 1 | 3% |
| San Francisco | 25 | 1 | - | - |
| San Joaquin | 33 | - | - | - |
| San Luis Obispo | 63 | 1 | - | - |
| San Mateo | 152 | 36 | - | - |
| Santa Barbara | 52 | 1 | - | - |
| Santa Clara | 145 | 27 | 1 | 4% |
| Santa Cruz | 52 | - | - | - |
| Shasta | 5 | - | - | - |
| Sierra | - | - | - | - |
| Siskiyou | 1 | - | - | - |
| Solano | 22 | 1 | - | - |
| Sonoma | 21 | 3 | - | - |
| Stanislaus | 25 | 3 | - | - |
| Sutter | 9 | - | - | - |
| Tehama | 3 | - | - | - |
| Trinity | 1 | - | - | - |
| Tulare | 8 | 2 | - | - |
| Tuolumne | 1 | - | - | - |
| Ventura | 32 | - | - | - |
| Yolo | 52 | 7 | - | - |
| Yuba | 7 | - | - | - |
| State Totals | 1897 | 203 | 4 | 2% |
* Birds in a die-off are not included in reported totals because the deaths are not related to WNV. A die-off is defined as a group of 10 or more same species dead birds unless the species is American Crow.
Source: Vector-Borne Disease Section, California Department of Public Health