County annual report · FIPS 06081
2021 San Mateo County, CA Power Outage Report
In 2021, customers in San Mateo County, CA went without power for an average of 8.2 hours, a total of 2.7M customer-hours (California average 6.6 hours). That ranks 30th worst of 57 California counties and 925th of 2,974 nationally.
Compared with CA, the US and 2020
Coverage line is EAGLE-I's share of California customers tracked each year.
Biggest outages in San Mateo County, 2021
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | October 21, 2021 05:00 | November 9, 2021 11:15 | 19d 6h | 46,910 | 1.1M |
| 2 | September 25, 2021 02:45 | September 26, 2021 04:15 | 1d 1h | 36,080 | 60K |
| 3 | March 8, 2021 13:00 | March 10, 2021 08:15 | 1d 19h | 19,254 | 17K |
| 4 | October 17, 2021 21:30 | October 18, 2021 17:30 | 20h | 18,276 | 121K |
| 5 | January 17, 2021 16:15 | January 26, 2021 12:30 | 8d 20h | 9,487 | 162K |
| 6 | April 26, 2021 14:45 | May 2, 2021 13:00 | 5d 22h | 9,174 | 15K |
| 7 | February 21, 2021 06:45 | February 26, 2021 03:30 | 4d 20h | 7,315 | 15K |
| 8 | November 19, 2021 14:30 | November 21, 2021 05:30 | 1d 15h | 6,583 | 13K |
| 9 | April 16, 2021 15:45 | April 17, 2021 03:30 | 11h 45m | 6,208 | 8,046 |
| 10 | December 12, 2021 08:30 | December 21, 2021 06:45 | 8d 22h | 6,030 | 130K |
Outage episodes by size in 2021: 185 reached 100+ customers, 68 reached 1,000+ customers, 4 reached 10,000+ customers.
Utility reliability filed with the EIA
SAIDI (average outage time per customer) and SAIFI (average interruptions per customer) that utilities serving San Mateo County reported on EIA Form 861 for 2021, or their most recent earlier filing. Utility-wide figures, not county-specific.
| Utility | EIA year | SAIDI | SAIFI | SAIDI excl. major events | SAIFI excl. major events |
|---|---|---|---|---|---|
| Pacific Gas & Electric Co. | 2021 | 10.4 hrs | 1.84 | 3.6 hrs | 1.32 |
| City & County of San Francisco | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 95% of California's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 328,408 customers (ORNL modeled county customer count), including major storm days. It is comparable across counties but is not the SAIDI a utility files.
- An outage event is a continuous stretch with customers out; counts at 100, 1,000 and 10,000+ use its peak.
- Years loaded: 2015–2025. San Mateo County has data for 2017–2025.
Cite this report
MassOutage (massoutage.com), San Mateo County, CA annual power outage report, 2021, data as of Oct 3, 2026 02:41 UTC, sources: DOE EAGLE-I (https://eagle-i.doe.gov/); EAGLE-I modeled customer counts (MCC) (https://figshare.com/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2021/california/san-mateo-county