(a) The department may assign a hazard classification to dams according to the potential impacts of a dam failure. The factors used to evaluate and assign a hazard classification are:

1. (1) the height, impoundment capacity and physical characteristics of the dam;
2. (2) the physical characteristics of the location of the dam, including the areas which would be affected by a failure of the dam; and

3. (3) the potential consequences and other circumstances relevant to the failure of the dam, including, without limitation:

   1. (i) personal injury and loss of human life;
   2. (ii) damage to developed areas, occupied buildings, or other land improvements;
   3. (iii) economic loss;
   4. (iv) damage to natural resources;
   5. (v) proximity to and possible impairment of access to emergency services; and
   6. (vi) other site-specific characteristics or factors which the department determines are necessary to consider.

(b) The hazard classifications for dams are assigned based on the particular physical characteristics of a dam and its location, may be assigned irrespective of the size of the dam, as appropriate, and are as follows:

1. (1) Class A or low hazard dam. A dam failure is unlikely to result in damage to anything more than isolated or unoccupied buildings, undeveloped lands, minor roads such as town or county roads; is unlikely to result in the interruption of important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; and/or is otherwise unlikely to pose the threat of personal injury, substantial economic loss or substantial environmental damage.
2. (2) Class B or intermediate hazard dam. A dam failure may result in damage to isolated homes, main highways, and minor railroads; may result in the interruption of important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; and/or is otherwise likely to pose the threat of personal injury and/or substantial economic loss or substantial environmental damage. Loss of human life is not expected.
3. (3) Class C or high hazard dam. A dam failure may result in widespread or serious damage to home(s); damage to main highways, industrial or commercial buildings, railroads, and/or important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; or substantial environmental damage; such that the loss of human life or widespread substantial economic loss is likely.
4. (4) Class D or negligible or no hazard dam. A dam that has been breached or removed, or has failed or otherwise no longer materially impounds waters, or a dam that was planned but never constructed. Class D dams are considered to be defunct dams posing negligible or no hazard. The department may retain pertinent records regarding such dams.