Concow

Concow is an arch dam located in Butte County, California, built in 1925. It carries a High hazard potential classification and has a satisfactory condition assessment.

About Concow

The primary purpose of Concow is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Thermalito Water And Sewer District (public utility). It impounds the Concow Creek near N/a.

The dam stands 94 feet tall and stretches 335 feet across, creates a reservoir covering 280 acres, has a maximum storage capacity of 6,370 acre-feet, and collects water from a drainage area of 14 square miles. Completed in 1925, the structure is over a century old.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 10/07/2025.

At 94 feet, this dam is taller than 98% of all dams in the United States.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The California dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateCalifornia
CountyButte
Nearest CityN/a
River/StreamConcow Creek
Coordinates39.76360, -121.52810

Physical Characteristics

Dam TypeArch
NID Height94 ft
Dam Height94 ft
Dam Length335 ft
Year Completed1925 (101 years old)

Storage & Hydraulics

NID Storage6,370 acre-ft
Max Storage6,370 acre-ft
Surface Area280 acres
Drainage Area14 sq mi

Ownership & Safety

PurposeWater Supply
OwnerThermalito Water and Sewer District
Owner TypePublic Utility
Hazard ClassificationHigh
Condition AssessmentSatisfactory
Last Inspection10/07/2025
Emergency Action PlanYes

Identifiers

NID IDCA00277
Federal IDCA00277
More InfoState Dam Safety Program

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