Source Water Assessment Areas

Source water assessment area (SWAA) is the Minnesota Department of Health (MDH) interim surface and subsurface area surrounding a public water supply well that completely contains the scientifically calculated time-of-travel (TOT) area. The primary purpose of the SWAA is to give the public water supplier an idea of the potential size of the final Wellhead Protection Area (WHPA). The TOT for a non-vulnerable SWAA (Meth_code = FRC) is 3 years and for a vulnerable SWAA (Meth_code = AM) is 10 years. Ultimately the SWAA will be replaced by a WHPA and a corresponding Drinking Water Supply Management Area (DWSMA).