PowerOutageHistory
Reliability Grade
A
Top tier
2017-2025
South Dakota

Walworth CountyPower Outage History

20172025 · South Dakota
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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.

Takeaway
Low outage risk
Reliability Rank
Fuller bar = more reliable
Nationwide94th pct
In South Dakota#14 of 65
See full South Dakota rankings →
Total events
150
Recorded 2017–2025
Avg duration
1.3 hrs
Per outage event
Longest outage
14 hrs
Single worst event on record
Customers served
5,439
Utility customers in county

Outages by year

Outages by month (seasonality)

Worst outage events on record

DateDurationCustomers affectedCause
Oct 14, 20214 hrs2,454 (45%)Drought
Jun 4, 20173 hrs2,073 (38%)Unnamed event
Sep 28, 2022<1 hr2,021 (37%)Unnamed event
Oct 18, 2017<1 hr1,777 (33%)Drought
Nov 14, 2017<1 hr1,717 (32%)Unnamed event

Was There an Outage on a Specific Date?

Pick a date to see whether a power outage was recorded for Walworth County, South Dakota that day.

Over the 9 years from 2017 to 2025, Walworth County recorded 150 distinct power outage events, averaging 1.3 hours per event.

The single worst outage on record in Walworth County started October 14, 2021 (Drought), lasting 4 hours and leaving up to 2,454 customers without power (45% of the county) at its peak.

July has historically been the worst month for outages in Walworth County, with 35 events recorded during that month across the dataset.

Based on this history, Walworth County earns a Reliability Grade of A, placing it in the 94th percentile nationally for grid reliability (higher percentile = more reliable).

Similar counties in South Dakota

Counties with the closest reliability grade and national percentile to Walworth County.

CountyGradeNational percentile
Buffalo CountyA94th
Campbell CountyA93rd
Potter CountyA94th
Edmunds CountyA93rd
Stanley CountyA93rd

Most reliable counties nationally

The top 3 counties nationally by reliability grade and percentile.

CountyStateGradeNational percentile
Clay CountySouth DakotaA100th
Clearwater CountyMinnesotaA99th
Limestone CountyAlabamaA99th

Least reliable counties nationally

The bottom 3 counties nationally by reliability grade and percentile.

FAQ

How often does power go out in Walworth County?

Between 2017 and 2025, Walworth County recorded 150 outage events, averaging 1.3 hours each.

What is Walworth County's reliability grade?

Walworth County has a Reliability Grade of A, in the 94th national percentile.

What was the worst power outage in Walworth County?

The worst outage on record started October 14, 2021 (Drought), lasting 4 hours and affecting up to 2,454 customers.

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Data: ORNL EAGLE-I Recorded Electricity Outages (2014–2025), CC BY 4.0. Storm names: NOAA Storm Events Database. Last data refresh: 2025. See methodology.