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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
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Proposing to Repair an Existing Dam

If you determine that your dam falls under permitting authority of the Dam Safety Act:

Step 1  Apply for a downstream Hazard Classification ($125 fee).

A hazard classification is required if construction is planned on any dam over 50 acre-feet in capacity, even if a classification was done in the past.  If your dam has been previously classified by the DNRC Dam Safety Program, please call your local Dam Safety Program Engineer to discuss first; in some circumstances, previously classified dams do not need a new hazard classification.

More information on Downstream Hazard Classification

Dams classified as high hazard, and containing over 50 acre foot of water, are required to obtain additional permits from the DNRC Dam Safety Program.

Step 2  If your dam is classified as “high hazard”, you must obtain a Construction Permit (no fee).

DNRC has adopted a new process based on a national model to make the construction permitting process more efficient and less prone to late stage design changes. The process requires early involvement of the Dam Safety Program in reviewing construction designs.  For more information please refer to the Dam Construction Design Review Process.

A Construction Permit is the final stage in the Design Review Process and must be accompanied by construction plans and specifications and an engineering design report.


Step 3  Obtain Other Applicable Permits

The dam owner is responsible for obtaining other applicable permits.  Other required permits depend on many factors including the type of dam owner (private, state, federal or local government), the owner of land under the dam (if different) and if the work is located on-stream or off-stream.  DNRC publishes an excellent reference Stream Permitting Guide that describes permits commonly needed to work on or near a body of water and who to contact for more information.

Note: If your repair involves increasing storage capacity of your reservoir, you must verify your water right supports this change. For more information please refer to:

Step 4  Once your repair is complete, you must obtain an Operation Permit

An Operation Permit is required in order to store water.  More information on Operation Permitting can be found at Permitting your Existing Dam.

FOR DAMS NOT SUBJECT TO DAM SAFETY ACT CONSTRUCTION PERMITTING REQUIREMENTS (Not classified as high hazard, or less than 50 acre feet) please refer to the informative video

Hiring an Engineer

For a list of licensed engineers who work on dams in Montana, please contact the Dam Safety Program