40 CFR §149.3

1. (a)All or part of an area which was designated as a sole or principal source aquifer prior to June 19, 1986, and for which an areawide ground-water quality protection plan was approved, under section 208 of the Clean Water Act, prior to that date; or
2. (b)All or part of a major recharge area of a sole or principal source aquifer, designated before June 19, 1988, for which:
   1. (1)The sole or principal source aquifer is particularly vulnerable to contamination due to the hydrogeologic characteristics of the unsaturated or saturated zone within the suggested critical aquifer protection area; and
   2. (2)Contamination of the sole or principal source aquifer is reasonably likely to occur, unless a program to reduce or prevent such contamination is implemented; and
   3. (3)In the absence of any program to reduce or prevent contamination, reasonably foreseeable contamination would result in significant cost, taking into account:
      1. (i)The cost of replacing the drinking water supply from the sole or principal source aquifer, and
      2. (ii)Other economic costs and environmental and social costs resulting from such contamination.