County annual report · FIPS 55133
2025 Waukesha County, WI Power Outage Report
In 2025, customers in Waukesha County, WI went without power for an average of 4.2 hours, a total of 602K customer-hours (Wisconsin average 3.9 hours). That ranks 23rd worst of 72 Wisconsin counties and 1715th of 3,000 nationally.
Compared with WI, the US and 2024
Coverage line is EAGLE-I's share of Wisconsin customers tracked each year.
Biggest outages in Waukesha County, 2025
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | August 9, 2025 16:45 | August 13, 2025 18:00 | 4d 1h | 14,153 | 298K |
| 2 | November 26, 2025 10:45 | November 28, 2025 00:00 | 1d 13h | 6,104 | 33K |
| 3 | March 15, 2025 04:30 | March 16, 2025 20:45 | 1d 16h | 6,057 | 27K |
| 4 | January 30, 2025 13:00 | January 31, 2025 10:30 | 21h 30m | 5,500 | 9,736 |
| 5 | April 14, 2025 17:45 | April 15, 2025 02:00 | 8h 15m | 4,308 | 3,551 |
| 6 | June 23, 2025 12:30 | June 24, 2025 12:30 | 1d | 4,099 | 6,429 |
| 7 | February 6, 2025 20:45 | February 7, 2025 08:30 | 11h 45m | 3,703 | 6,006 |
| 8 | May 21, 2025 21:00 | May 22, 2025 01:45 | 4h 45m | 3,634 | 3,865 |
| 9 | July 6, 2025 06:45 | July 7, 2025 00:00 | 17h 15m | 3,554 | 9,435 |
| 10 | May 15, 2025 21:30 | May 18, 2025 08:15 | 2d 10h | 3,497 | 12K |
Outage episodes by size in 2025: 97 reached 100+ customers, 28 reached 1,000+ customers, 1 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 Waukesha County reported on EIA Form 861 for 2025, 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 |
|---|---|---|---|---|---|
| Wisconsin Electric Power Co | 2024 | 4.9 hrs | 1.04 | 1.8 hrs | 0.74 |
| Oconomowoc Utilities | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about n/a of Wisconsin's customers in 2025; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 143,177 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. Waukesha County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Waukesha County, WI annual power outage report, 2025, 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/2025/wisconsin/waukesha-county