| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 345 | 5 | 5 | 100% |
| Alpine | - | - | - | - |
| Amador | 2 | - | - | - |
| Butte | 47 | 9 | - | - |
| Calaveras | 7 | - | - | - |
| Colusa | 8 | 3 | - | - |
| Contra Costa | 320 | 25 | - | - |
| Del Norte | - | - | - | - |
| El Dorado | 49 | 12 | - | - |
| Fresno | 97 | 7 | 4 | 57% |
| Glenn | 6 | - | - | - |
| Humboldt | 10 | - | - | - |
| Imperial | 3 | - | - | - |
| Inyo | - | - | - | - |
| Kern | 31 | 4 | 1 | 25% |
| Kings | 16 | - | - | - |
| Lake | 13 | 5 | - | - |
| Lassen | - | - | - | - |
| Los Angeles | 495 | 50 | - | - |
| Madera | 11 | 2 | - | - |
| Marin | 46 | 1 | - | - |
| Mariposa | - | - | - | - |
| Mendocino | 7 | - | - | - |
| Merced | 27 | 3 | - | - |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 23 | 3 | - | - |
| Napa | 21 | 5 | - | - |
| Nevada | 22 | 1 | - | - |
| Orange | 237 | 48 | - | - |
| Placer | 152 | 51 | - | - |
| Plumas | 3 | - | - | - |
| Riverside | 122 | 29 | - | - |
| Sacramento | 509 | 167 | 5 | 3% |
| San Benito | 4 | 1 | - | - |
| San Bernardino | 80 | 17 | - | - |
| San Diego | 287 | 92 | 8 | 9% |
| San Francisco | 54 | 4 | - | - |
| San Joaquin | 121 | 31 | 2 | 6% |
| San Luis Obispo | 40 | 4 | - | - |
| San Mateo | 370 | 108 | - | - |
| Santa Barbara | 35 | 12 | - | - |
| Santa Clara | 530 | 96 | 14 | 15% |
| Santa Cruz | 60 | 20 | - | - |
| Shasta | 12 | 3 | - | - |
| Sierra | 1 | - | - | - |
| Siskiyou | 3 | - | - | - |
| Solano | 84 | 9 | - | - |
| Sonoma | 93 | 7 | - | - |
| Stanislaus | 118 | 6 | - | - |
| Sutter | 10 | 2 | - | - |
| Tehama | 8 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 46 | 14 | 5 | 36% |
| Tuolumne | 4 | - | - | - |
| Ventura | 94 | 7 | - | - |
| Yolo | 142 | 21 | - | - |
| Yuba | 19 | 7 | - | - |
| State Totals | 4845 | 891 | 44 | 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