Chester CountyPower Outage History
What this grade means
Worse than average — more frequent or longer outages than most counties. This county's recorded history shows more frequent outages and/or longer restoration times than most US counties over the same 12-year period. If you live here, it's worth taking backup power more seriously than an average household would.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Aug 4, 2020 | 131 hrs | 110,546 (41%) | Tropical Storm Isaias |
| Jul 17, 2024 | 94 hrs | 77,059 (29%) | Excessive Heat |
| Jun 23, 2015 | 20 hrs | 75,718 (28%) | Heat |
| Jun 3, 2020 | 129 hrs | 72,581 (27%) | Thunderstorm Wind |
| Jan 9, 2024 | 76 hrs | 65,902 (25%) | Winter Weather |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Chester County, Pennsylvania that day.
Over the 12 years from 2014 to 2025, Chester County recorded 4,216 distinct power outage events, averaging 2.2 hours per event.
The single worst outage on record in Chester County started August 4, 2020 (Tropical Storm Isaias), lasting 131 hours and leaving up to 110,546 customers without power (41% of the county) at its peak.
July has historically been the worst month for outages in Chester County, with 553 events recorded during that month across the dataset.
Based on this history, Chester County earns a Reliability Grade of D, placing it in the 23rd percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Pennsylvania
Counties with the closest reliability grade and national percentile to Chester County.
| County | Grade | National percentile |
|---|---|---|
| Armstrong County | D | 23rd |
| Perry County | D | 23rd |
| Venango County | D | 24th |
| Bucks County | D | 24th |
| Columbia County | D | 27th |
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 Chester County?
Between 2014 and 2025, Chester County recorded 4,216 outage events, averaging 2.2 hours each.
What is Chester County's reliability grade?
Chester County has a Reliability Grade of D, in the 23rd national percentile.
What was the worst power outage in Chester County?
The worst outage on record started August 4, 2020 (Tropical Storm Isaias), lasting 131 hours and affecting up to 110,546 customers.