Section 144-232-5-502.0 - Guidelines for Standing Column Wells502.1Total depth: The total depth of a standing column well is determined by adding the following items:a Depth to the static water level,b Drawdown resulting from domestic water use, if any,c Drawdown resulting from geothermal bleed, if any,d Recirculation distance between the pump intake and the discharge of the return line, ande Length of sump in the bottom of the well. 502.2Recirculation distance: The minimum recommended recirculation distance per ton of heat pump capacity for a single family residential detached home is as follows:a 125 feet for a geothermal well with no bleed,b 85 feet for a geothermal well with a 10% bleed,c 75 feet for a geothermal well with a 20% bleed, andd 60 feet for a geothermal well with a 30% bleed. 502.3Pump tests: It is recommended that a pump test, sufficient to evaluate the actual drawdown in the well, be completed for standing column wells to be used for domestic water and/or bleed water. The pumping rate to be used for the pump test should be no less than the total of the domestic water use and any anticipated geothermal bleed. The pump test should proceed until water levels are stabilized in the well. For standing-column wells, it is recommended that a driller's log be recorded and include the following: b Total length and diameter of casing installed and the total depth and diameter of borehole.c Depth and yield of each water-bearing fracture and the static water level.d In the same manner as used for closed loop wells, identification of the material of which each stratum is composed.e Identification and description of any potentially troublesome zones in the uncased borehole.f Tonnage of heat pump to be served by the standing column wellg Design heat pump pumping rate for the well.h Recommended depth setting of pump in the well.i Recommended maximum bleed rate for the system.j Recommended depth setting of the return pipe in the well.k Time at which pumping started.l Record of pumping rates and pumping water levels recorded during the test.m Time at which pumping stopped. 502.4Pump depth: The depth of the pump setting and the depth of the discharge of the return pipe in the well shall be determined from the results of the pump test and shall be set so the discharge of the return pipe and the pump intake shall always be submerged below the lowest pumping water level.502.5Sediment filters: A sediment or spin-down filter should be installed on the intake line before the heat pump to prevent sediment from the well damaging the heat pump heat exchanger.502.6Additional design requirements: Before drilling any standing column well to be utilized as a heat source for any structure other than a single-family, residential, detached home and associated structures (for example, garages and other outbuildings), the driller shall first obtain a design for that specific well provided by either a Professional Engineer (PE) or a Certified Geothermal Designer (CGD)502.7Maine DEP requirements: A driller who drills either a standing column well with bleed, or an open-to-recycle well, and a pump installer who installs a pump system into such a well, shall perform the work in accordance with current Maine Department of Environmental Protection rules regulating the proper discharge of water from the well to a location other than back into the same well.10-144 C.M.R. ch. 232, § 5-502.0