| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 344 | 80 | 20 | 25% |
| Alpine | - | - | - | - |
| Amador | 16 | 1 | - | - |
| Butte | 102 | 30 | 4 | 13% |
| Calaveras | 8 | - | - | - |
| Colusa | 7 | 1 | - | - |
| Contra Costa | 711 | 45 | 13 | 29% |
| Del Norte | 3 | 1 | - | - |
| El Dorado | 94 | 22 | 2 | 9% |
| Fresno | 162 | 4 | - | - |
| Glenn | 6 | - | - | - |
| Humboldt | 24 | 5 | 1 | 20% |
| Imperial | 1 | - | - | - |
| Inyo | 2 | - | - | - |
| Kern | 43 | 3 | 1 | 33% |
| Kings | 14 | 2 | - | - |
| Lake | 21 | 7 | - | - |
| Lassen | - | - | - | - |
| Los Angeles | 839 | 92 | 19 | 21% |
| Madera | 13 | 2 | - | - |
| Marin | 59 | 1 | - | - |
| Mariposa | - | - | - | - |
| Mendocino | 10 | - | - | - |
| Merced | 55 | 1 | - | - |
| Modoc | - | - | - | - |
| Mono | - | - | - | - |
| Monterey | 34 | 4 | - | - |
| Napa | 19 | 4 | - | - |
| Nevada | 26 | 5 | - | - |
| Orange | 518 | 389 | 18 | 5% |
| Placer | 465 | 214 | 44 | 21% |
| Plumas | 2 | - | - | - |
| Riverside | 166 | 32 | 6 | 19% |
| Sacramento | 1542 | 554 | 241 | 44% |
| San Benito | 9 | 1 | - | - |
| San Bernardino | 154 | 20 | - | - |
| San Diego | 186 | 90 | 1 | 1% |
| San Francisco | 56 | 3 | - | - |
| San Joaquin | 208 | 42 | 16 | 38% |
| San Luis Obispo | 23 | 6 | - | - |
| San Mateo | 409 | 127 | 5 | 4% |
| Santa Barbara | 34 | 6 | - | - |
| Santa Clara | 700 | 237 | 56 | 24% |
| Santa Cruz | 132 | 46 | 2 | 4% |
| Shasta | 37 | 9 | 5 | 56% |
| Sierra | 1 | - | - | - |
| Siskiyou | 1 | - | - | - |
| Solano | 134 | 15 | - | - |
| Sonoma | 113 | 13 | - | - |
| Stanislaus | 151 | 8 | 1 | 13% |
| Sutter | 76 | 24 | 4 | 17% |
| Tehama | 18 | 4 | - | - |
| Trinity | 2 | - | - | - |
| Tulare | 61 | 10 | - | - |
| Tuolumne | 13 | 2 | 1 | 50% |
| Ventura | 97 | 15 | - | - |
| Yolo | 253 | 92 | 41 | 45% |
| Yuba | 42 | 17 | - | - |
| State Totals | 8216 | 2286 | 501 | 22% |
* 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