| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 213 | 83 | - | - |
| Alpine | - | - | - | - |
| Amador | 4 | - | - | - |
| Butte | 67 | 21 | 1 | 5% |
| Calaveras | 8 | - | - | - |
| Colusa | 7 | 1 | - | - |
| Contra Costa | 321 | 23 | 1 | 4% |
| Del Norte | - | - | - | - |
| El Dorado | 47 | 14 | - | - |
| Fresno | 344 | 16 | 10 | 63% |
| Glenn | 3 | - | - | - |
| Humboldt | 8 | 4 | - | - |
| Imperial | 1 | - | - | - |
| Inyo | 14 | - | - | - |
| Kern | 27 | 2 | 2 | 100% |
| Kings | 15 | - | - | - |
| Lake | 12 | 2 | - | - |
| Lassen | 2 | - | - | - |
| Los Angeles | 694 | 181 | 52 | 29% |
| Madera | 9 | - | - | - |
| Marin | 53 | 5 | - | - |
| Mariposa | 1 | - | - | - |
| Mendocino | 7 | - | - | - |
| Merced | 40 | 5 | 3 | 60% |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 21 | 5 | - | - |
| Napa | 25 | 1 | - | - |
| Nevada | 4 | 3 | - | - |
| Orange | 621 | 489 | 50 | 10% |
| Placer | 184 | 119 | 3 | 3% |
| Plumas | 2 | - | - | - |
| Riverside | 116 | 40 | 5 | 13% |
| Sacramento | 738 | 317 | 44 | 14% |
| San Benito | 3 | 1 | - | - |
| San Bernardino | 105 | 21 | 4 | 19% |
| San Diego | 175 | 124 | 2 | 2% |
| San Francisco | 47 | 5 | - | - |
| San Joaquin | 137 | 33 | 5 | 15% |
| San Luis Obispo | 29 | 6 | - | - |
| San Mateo | 233 | 64 | - | - |
| Santa Barbara | 22 | 2 | - | - |
| Santa Clara | 442 | 151 | 8 | 5% |
| Santa Cruz | 94 | 22 | - | - |
| Shasta | 19 | 1 | 1 | 100% |
| Sierra | - | - | - | - |
| Siskiyou | 1 | - | - | - |
| Solano | 55 | 12 | - | - |
| Sonoma | 54 | 6 | - | - |
| Stanislaus | 142 | 15 | 4 | 27% |
| Sutter | 49 | 10 | - | - |
| Tehama | 6 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 135 | 32 | 18 | 56% |
| Tuolumne | 15 | 2 | 1 | 50% |
| Ventura | 92 | 18 | 2 | 11% |
| Yolo | 181 | 67 | 7 | 10% |
| Yuba | 36 | 9 | 3 | 33% |
| State Totals | 5681 | 1932 | 226 | 12% |
* 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