Sumter County Power Outage History
2014–2025 · South Carolina
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 |
|---|---|---|---|
| Oct 8, 2016 | 12 hrs | 27,446 (31%) | Hurricane Matthew |
| Oct 8, 2016 | 120 hrs | 26,512 (30%) | Hurricane Matthew |
| Jun 20, 2025 | 0 hrs | 22,428 (26%) | Heavy Rain |
| Apr 8, 2021 | 6 hrs | 15,457 (18%) | Unnamed event |
| Jul 13, 2019 | 3 hrs | 14,520 (17%) | Unnamed event |
Over the 12 years from 2014 to 2025, Sumter County recorded 775 distinct power outage events, averaging 2.5 hours per event.
The single worst outage on record in Sumter County started October 8, 2016 (Hurricane Matthew), lasting 12 hours and leaving up to 27,446 customers without power (31% of the county) at its peak.
August has historically been the worst month for outages in Sumter County, with 113 events recorded during that month across the dataset.
Based on this history, Sumter County earns a Reliability Grade of C, placing it in the 56th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Sumter County's outage profile
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Similar counties in South Carolina
Counties with the closest reliability grade and national percentile to Sumter County.
| County | Grade | National percentile |
|---|---|---|
| Marlboro County | C | 55th |
| Jasper County | C | 54th |
| Clarendon County | C | 58th |
| Williamsburg County | C | 52nd |
| Calhoun County | B | 60th |
FAQ
How often does power go out in Sumter County?
Between 2014 and 2025, Sumter County recorded 775 outage events, averaging 2.5 hours each.
What is Sumter County's reliability grade?
Sumter County has a Reliability Grade of C, in the 56th national percentile.
What was the worst power outage in Sumter County?
The worst outage on record started October 8, 2016 (Hurricane Matthew), lasting 12 hours and affecting up to 27,446 customers.