| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 61 | - | - | - |
| Alpine | - | - | - | - |
| Amador | 2 | - | - | - |
| Butte | 10 | - | - | - |
| Calaveras | 1 | - | - | - |
| Colusa | 2 | - | - | - |
| Contra Costa | 111 | 6 | 1 | 17% |
| Del Norte | - | - | - | - |
| El Dorado | 8 | 2 | - | - |
| Fresno | 31 | - | - | - |
| Glenn | 2 | - | - | - |
| Humboldt | - | - | - | - |
| Imperial | - | - | - | - |
| Inyo | - | - | - | - |
| Kern | 9 | - | - | - |
| Kings | 5 | - | - | - |
| Lake | - | - | - | - |
| Lassen | - | - | - | - |
| Los Angeles | 216 | 17 | - | - |
| Madera | 3 | 1 | - | - |
| Marin | 11 | 1 | - | - |
| Mariposa | - | - | - | - |
| Mendocino | - | - | - | - |
| Merced | 13 | - | - | - |
| Modoc | - | - | - | - |
| Mono | - | - | - | - |
| Monterey | 4 | 1 | - | - |
| Napa | 2 | - | - | - |
| Nevada | 6 | - | - | - |
| Orange | 143 | 107 | - | - |
| Placer | 26 | - | - | - |
| Plumas | - | - | - | - |
| Riverside | 20 | - | - | - |
| Sacramento | 168 | 49 | - | - |
| San Benito | 1 | - | - | - |
| San Bernardino | 21 | 6 | - | - |
| San Diego | 45 | 16 | - | - |
| San Francisco | 5 | - | - | - |
| San Joaquin | 45 | 10 | - | - |
| San Luis Obispo | 9 | - | - | - |
| San Mateo | 51 | 4 | - | - |
| Santa Barbara | 7 | - | - | - |
| Santa Clara | 126 | 18 | - | - |
| Santa Cruz | 18 | 3 | - | - |
| Shasta | 12 | 1 | - | - |
| Sierra | - | - | - | - |
| Siskiyou | 1 | - | - | - |
| Solano | 34 | 2 | - | - |
| Sonoma | 21 | 4 | - | - |
| Stanislaus | 46 | - | - | - |
| Sutter | 8 | 3 | - | - |
| Tehama | 1 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 11 | 5 | - | - |
| Tuolumne | 2 | - | - | - |
| Ventura | 17 | - | - | - |
| Yolo | 29 | 7 | - | - |
| Yuba | 1 | - | - | - |
| State Totals | 1365 | 263 | 1 | 0% |
* 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