| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 719 | 39 | 39 | 100% |
| Alpine | - | - | - | - |
| Amador | 16 | - | - | - |
| Butte | 51 | 11 | 1 | 9% |
| Calaveras | 11 | - | - | - |
| Colusa | 7 | 1 | - | - |
| Contra Costa | 444 | 70 | 15 | 21% |
| Del Norte | 5 | - | - | - |
| El Dorado | 29 | 9 | 1 | 11% |
| Fresno | 151 | 19 | 3 | 16% |
| Glenn | 2 | - | - | - |
| Humboldt | 16 | - | - | - |
| Imperial | 3 | - | - | - |
| Inyo | 2 | - | - | - |
| Kern | 35 | 3 | - | - |
| Kings | 16 | - | - | - |
| Lake | 15 | 8 | - | - |
| Lassen | 2 | - | - | - |
| Los Angeles | 1978 | 248 | 165 | 67% |
| Madera | 34 | 5 | 3 | 60% |
| Marin | 82 | 4 | - | - |
| Mariposa | 6 | - | - | - |
| Mendocino | 9 | - | - | - |
| Merced | 38 | 4 | 2 | 50% |
| Modoc | 4 | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 71 | 3 | - | - |
| Napa | 38 | 9 | 1 | 11% |
| Nevada | 29 | 4 | - | - |
| Orange | 790 | 250 | 120 | 48% |
| Placer | 239 | 105 | 9 | 9% |
| Plumas | 2 | - | - | - |
| Riverside | 277 | 58 | 15 | 26% |
| Sacramento | 1002 | 412 | 107 | 26% |
| San Benito | 6 | - | - | - |
| San Bernardino | 192 | 51 | 20 | 39% |
| San Diego | 624 | 261 | 101 | 39% |
| San Francisco | 85 | 12 | - | - |
| San Joaquin | 168 | 57 | 14 | 25% |
| San Luis Obispo | 156 | 9 | - | - |
| San Mateo | 597 | 149 | 10 | 7% |
| Santa Barbara | 84 | 6 | - | - |
| Santa Clara | 1010 | 291 | 122 | 42% |
| Santa Cruz | 113 | 14 | - | - |
| Shasta | 30 | 3 | - | - |
| Sierra | - | - | - | - |
| Siskiyou | 4 | - | - | - |
| Solano | 77 | 12 | 2 | 17% |
| Sonoma | 158 | 9 | 1 | 11% |
| Stanislaus | 129 | 17 | 1 | 6% |
| Sutter | 35 | 10 | 3 | 30% |
| Tehama | 5 | - | - | - |
| Trinity | 1 | - | - | - |
| Tulare | 39 | 8 | - | - |
| Tuolumne | 2 | - | - | - |
| Ventura | 135 | 32 | 7 | 22% |
| Yolo | 204 | 93 | 20 | 22% |
| Yuba | 41 | 8 | 4 | 50% |
| State Totals | 10019 | 2304 | 786 | 34% |
* 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