The minimum horizontal distance between a water-supply well and the ordinary high water level of a stream, river, pond, storm water retention pond, or lake is 35 feet. The isolation distance does not apply to:
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;
a wetland, grassed waterway, depression, culvert, or ditch holding water less than six months of the year; or
an artificial pond holding less than 5,000 gallons of water.
A water-supply well must be constructed to prevent the entry of flood water into the well by:
extending the casing at least five feet above the regional flood level;
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;
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
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.
17 SR 2773; 33 SR 211
September 2, 2008
Official Publication of the State of Minnesota
Revisor of Statutes