Table 1 - Required Minimum Separation Distances to Protect Water Wells From Contamination
Contaminant Source | Distance (Feet) 1 |
Chemical storage sites not protected from the elements (e.g., salt and sand/salt storage) 2 | 300 |
Landfill waste disposal area, or hazardous or radiological waste disposal area 2 | 300 |
Land surface application or subsurface injection of effluent or digested sludge from a municipal or public wastewater treatment facility | 200 |
Land surface application or subsurface injection of septage waste | 200 |
Land surface spreading or subsurface injection of liquid or solid manure 3 | 200 |
Storage areas for manure piles 4 | 200 |
Barnyard, silo, barn gutters and animal pens 5,6 | 100 |
Cesspools (i.e. pits with no septic tank pretreatment) | 200 |
Wastewater treatment absorption systems located in coarse gravel or in the direct path of drainage to a well | 200 |
Fertilizer and/or pesticide mixing and/or clean up areas | 150 |
Seepage pit (following septic tank) 5 | 150 |
Underground single walled chemical or petroleum storage vessels | 150 |
Absorption field or bed 5 | 100 |
Contained chemical storage sites protected from the elements (e.g., salt and sand/salt storage within covered structures) 7 | 100 |
Septic system components (non-watertight) 5 | 100 |
Intermittent sand filter without a watertight liner 5 | 100 |
Sanitary privy pit 5 | 100 |
Surface wastewater recharge absorption system constructed to discharge storm water from parking lots, roadways or driveways 5 | 100 |
Cemeteries | 100 |
Sanitary privy with a watertight vault | 50 |
Septic tank, aerobic unit, watertight effluent line to distribution box | 50 |
Sanitary sewer or combined sewer | 50 |
Surface water recharge absorption system with no automotive-related wastes (e.g., clear-water basin, clear-water dry well) | 50 |
Stream, lake, watercourse, drainage ditch, or wetland | 25 |
All known sources of contamination otherwise not shown above | 100 |
Notes for Table 1:
1 The listed water well separation distances from contaminant sources shall be increased by 50% whenever aquifer water enters the water well at less than 50 feet below grade. If a 50% increase in separation distances can not be achieved, then the greatest possible increase in separation distance shall be provided with such additional measures as needed to prevent contamination. See also Note 6 to Table 2.
2 Water wells shall not be located in a direct line of flow from these items, nor in any contaminant plume created by these items, except with such additional measures (e.g., sentinel groundwater monitoring, hydraulic containment, source water treatment) as needed to prevent contamination.
3 Based upon on-site evaluations of agricultural properties done per agricultural environmental management (AEM) or comprehensive nutrient management plan (CNMP) programs by a certified nutrient management planner or soil and water conservation district (SWCD) official, water wells may be located a minimum of 100 feet from areas subject to land spreading of manure.
4 Water wells may be located 100 feet from temporary (30 days or less) manure piles/staging areas that are controlled to preclude contamination of surface or groundwater or 100 feet from otherwise managed manure piles that are controlled pursuant to regulation in a manner that prevents contamination of surface or groundwater.
5 When these contamination sources are located in coarse gravel or are located upgrade and in the direct path of drainage to a water well, the water well shall be located at least 200 feet away from the closest part of these sources.
6 Animal pen does not include small pet shelters or kennels housing 3 or fewer adult pets.
7 Chemical storage sites as used in this entry do not include properly maintained storage areas of chemicals used for water treatment nor areas of household quantities of commonly used domestic chemicals.