WATER-SUPPLY WELL DISTANCE FROM WATER BODIES; PROTECTIONS IN FLOOD AREAS

Subpart 1. Distance from water bodies. The minimum horizontal distance between a water-supply well and the ordinary high water level of a stream, river, pond, stormwater retention pond, or lake is 35 feet. The isolation distance does not apply to: A. an area protected by a flood control structure accepted by the United States Federal Emergency Management Agency (FEMA), as designated on a FEMA flood map; B. a wetland, grassed waterway, depression, culvert, or ditch holding water less than six months of the year; or C. an artificial pond holding less than 5,000 gallons of water. Subp. 2. Flood protection. A water-supply well must be constructed to prevent the entry of flood water into the well by: A. extending the casing at least five feet above the regional flood level; B. installing a watertight seal and extending the casing ten feet above the established ground surface, if the regional flood level is more than five feet above the established ground surface; C. installing an outer, neat-cement grouted protective casing in accordance with part 4725.6755 , subpart 2, item B, extending the protective casing and well casing a minimum of two feet above the established ground surface, and installing a waterproof threaded cap or a waterproof compression seal with drawbolts and a one-piece top plate on both casings; or D. extending the casing a minimum of two feet above the established ground surface, installing a sealed spool, or flowing well pitless unit, and installing a waterproof, nonvented compression seal. The requirements in this subpart do not apply to a water-supply well located in an area protected by a flood control structure accepted by the United States Federal Emergency Management Agency (FEMA), as designated on a FEMA flood map.