Williamson CountyPower Outage History
What this grade means
(How grades are calculated)Top 20% most reliable nationally — infrequent, short outages. This county ranks in the most reliable fifth of all US counties in our dataset, based on 12 years of real DOE outage records: outages happen less often here, and when they do occur they tend to be resolved quickly compared to the rest of the country. Baseline outage risk is low, though a severe local storm can still occasionally cause a longer-than-usual outage regardless of the long-term track record.
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Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| May 3, 2020 | <1 hr | 12,540 (10%) | Thunderstorm Wind |
| May 3, 2020 | 1 hrs | 12,499 (10%) | Thunderstorm Wind |
| May 4, 2020 | <1 hr | 12,179 (10%) | Thunderstorm Wind |
| May 4, 2020 | 2 hrs | 11,396 (9%) | Thunderstorm Wind |
| Jul 1, 2023 | 10 hrs | 11,340 (9%) | Thunderstorm Wind |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Williamson County, Tennessee that day.
Over the 12 years from 2014 to 2025, Williamson County recorded 800 distinct power outage events, averaging 1.4 hours per event.
The single worst outage on record in Williamson County started May 3, 2020 (Thunderstorm Wind), lasting less than 1 hour and leaving up to 12,540 customers without power (10% of the county) at its peak.
June has historically been the worst month for outages in Williamson County, with 100 events recorded during that month across the dataset.
Based on this history, Williamson County earns a Reliability Grade of A, placing it in the 90th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Tennessee
Counties with the closest reliability grade and national percentile to Williamson County.
| County | Grade | National percentile |
|---|---|---|
| Hamblen County | A | 90th |
| Gibson County | A | 88th |
| Overton County | A | 88th |
| Hamilton County | A | 88th |
| Anderson County | A | 91st |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
FAQ
How often does power go out in Williamson County?
Between 2014 and 2025, Williamson County recorded 800 outage events, averaging 1.4 hours each.
What is Williamson County's reliability grade?
Williamson County has a Reliability Grade of A, in the 90th national percentile.
What was the worst power outage in Williamson County?
The worst outage on record started May 3, 2020 (Thunderstorm Wind), lasting less than 1 hour and affecting up to 12,540 customers.