Mills Reservoir Report

Last Updated: December 5, 2025

Mills, a private water supply dam located in Sacramento, California, serves the primary purpose of providing irrigation and water supply.


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Summary

Completed in 1952, this earth-type dam stands at a height of 23 feet with a hydraulic height of 18.5 feet, holding a storage capacity of 195 acre-feet. With a drainage area of 0.33 square miles along the Tr Cosumnes River, Mills plays a crucial role in the local water resource management.

Owned and regulated by the state of California, Mills is subject to regular inspections to ensure its safety and functionality. The dam has a high hazard potential but has been assessed to be in satisfactory condition as of September 2017. With state permitting, inspection, and enforcement in place, Mills is equipped to handle emergencies and mitigate risks effectively. The last inspection in February 2021 indicated a satisfactory condition, emphasizing the importance of ongoing monitoring and maintenance.

With its critical role in water supply and irrigation, Mills stands as a vital infrastructure in the Sacramento region. Managed by private owners and regulated by state agencies, this dam represents a key component of the local water management system. As climate change continues to impact water resources, facilities like Mills will play an increasingly important role in ensuring a reliable and sustainable water supply for the community.

Year Completed

1952

Dam Length

1050

Dam Height

23

River Or Stream

Tr Cosumnes Rv

Primary Dam Type

Earth

Surface Area

23

Hydraulic Height

18.5

Drainage Area

0.33

Nid Storage

195

Hazard Potential

High

Nid Height

23
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.