Frequently Asked Questions

What benefits do dams provide?

Dams offer many benefits ranging from irrigation, drinking water supply, flood control, renewable energy, recreation, transportation, and environmental enhancements. In particular, dams with storage can play a significant societal role during extreme weather conditions like floods and droughts. 

As a dam owner, do I need a state permit to operate my dam?

Generally, yes. Each state has their own regulations for dams in their state. A dam owner should consult the specific regulations for their state. For example, the Commonwealth of Virginia excludes dams from regulation dams if they are:

  1. Less than 6 feet high – measured from the downstream toe of the dam to the top of the dam.
  2. Less than 25 feet high and have a capacity of less than 50 acre-feet of capacity measured from the top of the dam.
  3. More than 25 feet high and have a capacity of less than 15 acre-feet .
  4. If the dam is operated for agricultural purposes, less than 25 feet high and have a capacity of less than 100 acre-feet.
  5. Licensed by the federal government.

Some states, like California, assume jurisdiction over dams even if the federal government also licenses the dam.

How are dams regulated?

 Dams are generally regulated according to their classification.

How are dams classified?

Dams are typically classified by their potential for loss of life or significant economic damage if the dam fails. A high hazard dam has the potential for either loss of life or significant economic damage. A low hazard dam would incur no expected loss of life or significant economic damage.  

What are the specific dam classifications in Virginia?

Virginia uses three dam classifications:

  1. High hazard – probable loss of life and significant economic damage upon failure.
  2. Significant hazard – might cause loss of life or appreciable economic damage upon failure,
  3. Low hazard – no loss of life or significant economic damage upon failure. 

If my dam is regulated, what do I need to do?

If your dam is regulated, you will need to obtain a state permit to operate it. In Virginia, you will need to apply for an Operation and Maintenance Certificate.

What does an application for a Virginia Operation and Maintenance Certificate require?

An application will require:

  1. An assessment of the dam by a licensed professional engineer.
  2. An emergency action plan.
  3. The required fee.

How long is Operation and Maintenance Certificate good for?

In Virginia, the Operation and Maintenance Certificate is good for six years and then must be renewed.

Are there annual requirements for an Operations and Maintenance Certificate?

Yes, a dam owner needs to conduct an annual inspection of the dam. This can be done either by the dam owner or a professional engineer.

What additional requirements for inspections are there for a high hazard dam?

A high hazard dam requires an inspection by a professional engineer every two years.

What is the requirement for a significant hazard dam?

A significant hazard dam must be inspected every three years by a professional engineer.

In Virginia, what does an owner require before constructing or altering a dam?

Prior to construction or alteration of a dam, an owner requires a construction or alteration permit.

Can a dam classification be changed?

Yes, if land uses change downstream and there is a greater potential for loss of life or significant economic loss.

If a dam classification changes, will a dam owner be required to meet more stringent regulations?

If the change is due to downstream uses, it is possible that more stringent standards might exist for a dam owner if the classification changes.

Why is a dam owner responsible for improvements to meet higher standards if the dam is reclassified?

If a dam has been in existence for years and provides public benefits, American dams believes that the owner should not bear sole responsibility for improving the dam. It is important to work with downstream land owners and local and state governments to address this issue. If an inundation study has been done, American Dams suggests that the dam owner be active and work with land owners to minimize development in the inundation area.

What is the view of American Dams on dam safety?

American Dams has similar goals to most state and federal dam safety officials. That is, dams should dams should be properly and safely designed, constructed, operated and maintained in a manner that protects public safety. Each dam owner should remain vigilant in keeping their dam safe. 

Regulators have adopted standards to protect the public from dam failures. Over time these standards have become more stringent. However, in a number of instances, the regulations have had unintended consequences on some dams, making the dams more costly to operate but providing little or no public benefit. If a dam owner believes that a regulation unfairly and unnecessarily affects their dam, American Dams will assist the dam owner in identifying and remedying any regulatory burden that does not benefit public safety.

Where can I get additional information on dam safety?

There are several sources available to a dam owner to obtain information on dam safety. The Federal Energy Regulatory Commission’s website at provides detailed information on dam safety. Go to Industries and Dam Safety and Inspections.

The United States Society on Dams web site also contains comprehensive information on dam safety. Their website is The National Hydropower Association has a dam safety program entitled Operational Excellence. Their website can be found at     

Can a dam owner receive grants to assist the owner in keeping their dam safe?

Yes, many states offer grants to dam owners in their state to assist the dam owner to ensure their dams remain safe. In the Virginia, the Virginia Resources Authority manages grants for the state. Grants are issued with a 50 percent match from the dam owner. Virginia allows grant monies to be used for items like dam break inundation zone analyses, hazard classification, emergency action plan development, and dam engineering and design. Applications are usually due to the state in the first quarter of the year.

What is the view of American Dams on environmental protection?


American Dams believes that all the public benefits of dams should be taken into consideration in the operation and maintenance of dams. American Dams is concerned that some organizations and agencies have goals to remove dams without due consideration of their public benefits. Dam owners should not be retroactively required to implement expensive measures to provide environmental enhancements. However, American Dams encourages dam owners to work with partners to protect and enhance the environment. The federal and state governments and a number of environmental organizations offer grants that can be used for environmental enhancements. American Dams will publish grant opportunities on our website as they become known.  

What happens if I want to add hydropower to my dam?

If a dam owner wants to add hydropower to their dam, they will need to file a preliminary permit application with the Federal Energy Regulatory Commission (FERC). In some circumstances, a dam owner can bypass the preliminary permit process and proceed directly to a license application or license exception from FERC. For more information dam owners should refer to FERC’s regulations at or consult an expert in FERC licensing. American Dams can provide a list of consultants in your area or additional information at no cost to a member of American Dams. 

Educational Resources

Tacoma Power Dams Save Fish


Serving more than 350,000 people, Tacoma Power dams produce clean, green and renewable power. Tacoma Power has invested millions into

improving fish passage, constructing two new hatcheries and researching safe fish collection.