Contra Costa County Power Outage History
2017–2025 · California
Average — typical outage frequency and duration nationally. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Mar 14, 2023 | 8 hrs | 80,988 (17%) | High Wind |
| Oct 27, 2019 | 3 hrs | 70,267 (14%) | Wildfire |
| Oct 27, 2019 | 5 hrs | 64,075 (13%) | Wildfire |
| Oct 28, 2019 | 4 hrs | 61,163 (13%) | Wildfire |
| Sep 29, 2019 | 1 hrs | 50,204 (10%) | Unnamed event |
Over the 9 years from 2017 to 2025, Contra Costa County recorded 4,148 distinct power outage events, averaging 3.0 hours per event.
The single worst outage on record in Contra Costa County started March 14, 2023 (High Wind), lasting 8 hours and leaving up to 80,988 customers without power (17% of the county) at its peak.
July has historically been the worst month for outages in Contra Costa County, with 484 events recorded during that month across the dataset.
Based on this history, Contra Costa County earns a Reliability Grade of C, placing it in the 59th percentile nationally for grid reliability (higher percentile = more reliable).
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Similar counties in California
Counties with the closest reliability grade and national percentile to Contra Costa County.
| County | Grade | National percentile |
|---|---|---|
| Sacramento County | C | 59th |
| Kern County | B | 60th |
| San Diego County | B | 61st |
| Santa Clara County | C | 56th |
| Tulare County | C | 56th |
FAQ
How often does power go out in Contra Costa County?
Between 2017 and 2025, Contra Costa County recorded 4,148 outage events, averaging 3.0 hours each.
What is Contra Costa County's reliability grade?
Contra Costa County has a Reliability Grade of C, in the 59th national percentile.
What was the worst power outage in Contra Costa County?
The worst outage on record started March 14, 2023 (High Wind), lasting 8 hours and affecting up to 80,988 customers.