NR 206.10(3)(d)(d) If the system has a design or average daily flow equal to or greater than 0.015 MGD, groundwater shall be monitored at a minimum of one level, at locations specified in the permit, and may include monitoring at more than one level. The department may waive this requirement on a case-by-case basis. Criteria which will be evaluated to waive this requirement include degree of treatment of the effluent, depth to groundwater and bedrock, nature of the bedrock, soil permeability, directions and rate of groundwater flow, vertical and horizontal flow gradients, existing groundwater quality, downgradient uses of the groundwater and compliance with ch. NR 140 standards.

NR 206.10(3)(e)(e) Groundwater elevation within the land disposal system shall be monitored through the use of a water table observation well for all land disposal systems that have a depth to groundwater from cell bottom of less than 5 feet.

NR 206.10(4)(a)(a) For systems where background water quality has been established, the groundwater sampling frequency shall be quarterly.

NR 206.10(4)(b)(b) For systems where background water quality has not been established, the groundwater sampling frequency shall be every 6 to 7 weeks until 8 representative samples have been obtained, and shall be quarterly thereafter.

NR 206.10(4)(c)(c) The department may modify the sampling frequency on a case-by-case basis.

NR 206.10(5)(a)(a) The department may require groundwater monitoring for any or all of the following parameters in filtered or unfiltered samples: elevation, BOD5, field specific conductance, COD, organic nitrogen, ammonia nitrogen, nitrate plus nitrite nitrogen, chlorides, sulfates, total dissolved solids, alkalinity, hardness, temperature and pH.

NR 206.10(5)(b)(b) Monitoring for other parameters may be required on a case-by-case basis if there is reason to believe contamination is occurring or if these contaminants are present in the wastewater, to determine compliance with the groundwater quality standards in ch. NR 140.

NR 206.10(7)(a)(a) The methods of analysis for substances contained in groundwater samples shall be those in ch. NR 219.

NR 206.10(7)(b)(b) Sample analysis used for permit reporting shall be performed by a laboratory certified or registered under ch. NR 149.