PURPOSE: This rule sets standards for open-loop heat pump systems that use wells to produce or return groundwater.

1. (1) Open-loop groundwater supply wells shall be constructed to domestic/multifamily well standards pursuant to 10 CSR 23- 3.030(1) if it produces less than seventy (70) gallons per minute and to high yield well standards pursuant to 10 CSR 23-3.030(3) if it produces more than seventy (70) gallons of water per minute. Any well that was constructed before October 1987 that is utilized as the water supply or return for an open-loop heat pump system is exempt from these rules, except that the surface disposal of the water may be subject to other regulations.
2. (2) Heat pump systems and surface disposal of used water may require a permit pursuant to 10 CSR 20-6.
3. (3) Open loop water return wells shall be constructed to domestic/multifamily well standards pursuant to 10 CSR 23-3.030(1) if it produces less than seventy (70) gallons per minute and to high yield well standards pursuant to 10 CSR 23-3.030(3) if it produces more than seventy (70) gallons of water per minute. The depth of the return well shall be a similar depth as the supply well and the water must be returned to the same aquifer. The water return pipe must extend at least twenty feet (20') below the static water level.

AUTHORITY: sections 256.606 and 256.626, RSMo 2016.* Emergency rule filed Nov. 16, 1993, effective Dec. 11, 1993, expired April 9, 1994. Original rule filed Aug. 17, 1993, effective March 10, 1994. Amended: Filed Nov. 1, 1995, effective June 30, 1996. Amended: Filed May 17, 2013, effective Dec. 30, 2013. Amended: Filed June 27, 2018, effective Feb. 28, 2019.

*Original authority: 256.606, RSMo 1991 and 256.626, RSMo 1985, amended 1991.