| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 706 | 67 | - | - |
| Alpine | 3 | - | - | - |
| Amador | 110 | 9 | - | - |
| Butte | 751 | 39 | 1 | 3% |
| Calaveras | 129 | 15 | - | - |
| Colusa | 46 | - | - | - |
| Contra Costa | 2227 | 115 | 3 | 3% |
| Del Norte | 27 | - | - | - |
| El Dorado | 543 | 37 | 1 | 3% |
| Fresno | 1232 | 82 | 2 | 2% |
| Glenn | 92 | 6 | 1 | 17% |
| Humboldt | 78 | 3 | - | - |
| Imperial | 35 | - | - | - |
| Inyo | 35 | 3 | - | - |
| Kern | 1590 | 150 | 1 | 1% |
| Kings | 133 | 6 | - | - |
| Lake | 94 | 3 | - | - |
| Lassen | 23 | - | - | - |
| Los Angeles | 5535 | 256 | 46 | 18% |
| Madera | 121 | 16 | - | - |
| Marin | 219 | 17 | - | - |
| Mariposa | 18 | 2 | - | - |
| Mendocino | 79 | 7 | - | - |
| Merced | 207 | 16 | - | - |
| Modoc | 17 | - | - | - |
| Mono | 11 | 1 | - | - |
| Monterey | 272 | 11 | - | - |
| Napa | 88 | 2 | - | - |
| Nevada | 305 | 35 | 3 | 9% |
| Orange | 2996 | 246 | 87 | 35% |
| Placer | 724 | 9 | - | - |
| Plumas | 57 | 11 | - | - |
| Riverside | 1269 | 40 | 4 | 10% |
| Sacramento | 3106 | 185 | 10 | 5% |
| San Benito | 34 | 2 | - | - |
| San Bernardino | 1554 | 83 | 7 | 8% |
| San Diego | 1742 | 153 | 62 | 41% |
| San Francisco | 105 | 9 | - | - |
| San Joaquin | 1509 | 109 | 23 | 21% |
| San Luis Obispo | 180 | 15 | - | - |
| San Mateo | 389 | 47 | 1 | 2% |
| Santa Barbara | 96 | 6 | - | - |
| Santa Clara | 961 | 46 | 6 | 13% |
| Santa Cruz | 163 | 12 | - | - |
| Shasta | 406 | 14 | 6 | 43% |
| Sierra | 16 | 1 | - | - |
| Siskiyou | 21 | 2 | - | - |
| Solano | 542 | 6 | - | - |
| Sonoma | 495 | 51 | - | - |
| Stanislaus | 938 | 65 | 6 | 9% |
| Sutter | 179 | 6 | 2 | 33% |
| Tehama | 137 | 8 | - | - |
| Trinity | 14 | 1 | - | - |
| Tulare | 754 | 104 | 29 | 28% |
| Tuolumne | 92 | 6 | - | - |
| Ventura | 553 | 40 | - | - |
| Yolo | 534 | 18 | - | - |
| Yuba | 103 | 5 | - | - |
| State Totals | 34395 | 2198 | 301 | 14% |
* 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