| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 110 | 6 | 2 | 33% |
| Alpine | - | - | - | - |
| Amador | - | - | - | - |
| Butte | 21 | 7 | - | - |
| Calaveras | - | - | - | - |
| Colusa | 2 | - | - | - |
| Contra Costa | 187 | 6 | - | - |
| Del Norte | - | - | - | - |
| El Dorado | 13 | 3 | - | - |
| Fresno | 54 | 4 | - | - |
| Glenn | 2 | - | - | - |
| Humboldt | 5 | - | - | - |
| Imperial | 1 | - | - | - |
| Inyo | - | - | - | - |
| Kern | 7 | 2 | - | - |
| Kings | 1 | - | - | - |
| Lake | 2 | - | - | - |
| Lassen | - | - | - | - |
| Los Angeles | 259 | 26 | 2 | 8% |
| Madera | 8 | - | - | - |
| Marin | 14 | - | - | - |
| Mariposa | 2 | - | - | - |
| Mendocino | 5 | - | - | - |
| Merced | 18 | 1 | - | - |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 6 | - | - | - |
| Napa | 8 | 1 | - | - |
| Nevada | 3 | - | - | - |
| Orange | 66 | 18 | - | - |
| Placer | 45 | 14 | - | - |
| Plumas | - | - | - | - |
| Riverside | 44 | 9 | 1 | 11% |
| Sacramento | 249 | 83 | 4 | 5% |
| San Benito | 4 | - | - | - |
| San Bernardino | 31 | 8 | - | - |
| San Diego | 81 | 30 | - | - |
| San Francisco | 24 | 7 | - | - |
| San Joaquin | 57 | 10 | - | - |
| San Luis Obispo | 14 | 2 | - | - |
| San Mateo | 111 | 24 | - | - |
| Santa Barbara | 9 | 5 | - | - |
| Santa Clara | 189 | 28 | 7 | 25% |
| Santa Cruz | 19 | 2 | - | - |
| Shasta | 4 | 1 | - | - |
| Sierra | - | - | - | - |
| Siskiyou | - | - | - | - |
| Solano | 27 | 10 | - | - |
| Sonoma | 27 | - | - | - |
| Stanislaus | 50 | - | - | - |
| Sutter | 13 | 2 | - | - |
| Tehama | 4 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 13 | 2 | - | - |
| Tuolumne | 1 | - | - | - |
| Ventura | 19 | 3 | - | - |
| Yolo | 83 | 19 | - | - |
| Yuba | 13 | 2 | - | - |
| State Totals | 1926 | 335 | 16 | 5% |
* 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