VENTING WATER-SUPPLY WELLS

Subpart 1. Venting exceptions. A water-supply well must be vented unless the well: A. is a flowing well; B. casing is used as a suction pipe; C. has a packer jet assembly; D. is used as a remedial well; or E. is constructed with a watertight seal in lieu of a casing extension as specified in part 4725.4350 , subpart 2. Subp. 2. Vent construction. A well vent must: A. be constructed of materials complying with parts 4725.2250 to 4725.2650 , or 4725.5150 , subpart 1; B. have watertight joints and terminate at least five feet above the regional flood level unless provided with a watertight seal as specified in part 4725.4350 , subpart 2; C. terminate a minimum of 12 inches above the established ground surface or the floor of a building as specified in part 4725.2175 , except that a vent for a community public water-supply well must terminate a minimum of 18 inches above the established ground surface and the floor of a building as specified in part 4725.2175 ; D. be screened with a noncorrosive mesh screen having openings of 1/16 inch or less and pointed downward; and E. be connected to the casing according to part 4725.4850 . Subp. 3. Screened vents. A screened vent incorporated into the underside of a well cap or cover may be used. Subp. 4. Gas. Any toxic or flammable gas must be vented from the well to the outside atmosphere.