DHS 157.96(2)(d)(d) Compliance. To judge compliance with the maximum contaminant levels listed in sub. (1), averages of data shall be used and shall be rounded to the same number of significant figures as the maximum contaminant level for the substance in question.

DHS 157.96(3)(a)1.1. Compliance with sub. (1) (a) shall be based on the analysis of an annual composite of 4 consecutive quarterly samples or the average of the analyses of 4 samples obtained at quarterly intervals.

DHS 157.96(3)(a)1.a.a. A gross alpha particle activity measurement may be substituted for the required radium-226 and radium-228 analyses provided that the measured gross alpha particle activity does not exceed 5 pCi/L at a confidence level of 95%, where 1.96 is the standard deviation of the net counting rate of the sample. In localities where radium-228 may be present in drinking water, the department may require radium-226 or radium-228 analyses or analyses of both when the gross alpha particle activity exceeds 2 pCi/L.

DHS 157.96(3)(a)2.2. A supplier of water shall monitor water supplies at least once every 4 years following the procedure required by subd. 1. At the discretion of the department, when the record taken in conformance with subd. 1. establishes that the average annual concentration is less than half the maximum contaminant levels established by sub. (1) (a), analysis of a single sample may be substituted for the quarterly sampling procedure required by subd. 1.

DHS 157.96(3)(a)2.a.a. When ordered by the department, more frequent monitoring shall be conducted in the vicinity of mining or other operations that may contribute alpha particle radioactivity to either surface or groundwater sources of drinking water.

DHS 157.96(3)(a)2.b.b. A supplier of water shall monitor in conformance with subd. 1. within one year of the introduction of a new water source for a community water system. More frequent monitoring shall be conducted when ordered by the department if possible contamination or changes in the distribution system or treatment processing occur that may increase the concentration of radioactivity in finished water.

DHS 157.96(3)(a)2.c.c. A community water system using 2 or more sources having different concentrations of radioactivity shall monitor source water and water from a free-flowing tap when required by the department.

DHS 157.96(3)(a)2.d.d. Monitoring for compliance with sub. (2) (a) need not include radium-228 except when required by the department, provided that the average annual concentration of radium-228 has been assayed at least once using the quarterly sampling procedure required by subd. 1.

DHS 157.96(3)(a)2.e.e. A supplier of water shall conduct annual monitoring of any community water system in which the radium-226 concentration exceeds 3 pCi/L, when required by the department.

DHS 157.96(3)(a)3.3. If the average annual maximum contaminant level for gross alpha particle activity or total radium as set forth in sub. (1) (a) is exceeded, the supplier of a community water system shall give notice to the department under sub. (7) and notify the public as required by sub. (8). Monitoring at quarterly intervals shall be continued until the annual average concentration no longer exceeds the maximum contaminant level or until a monitoring schedule as a condition to a variance, exemption or enforcement action is no longer in effect.

DHS 157.96(3)(b)1.1. Community water systems using surface water sources and serving more than 100,000 persons and any other community water systems as are designated by the department shall be monitored for compliance with sub. (1) (b) by analysis of a composite of 4 consecutive quarterly samples or analysis of 4 quarterly samples. Compliance with sub. (1) (b) may be assumed without further analysis if the average annual concentration of gross beta particle activity is less than 50 pCi/L and if the average annual concentrations of tritium and strontium-90 are less than those listed in Table 157.96A, provided that if both radionuclides are present, the sum of their annual dose equivalents to bone marrow does not exceed 4 millirem.

DHS 157.96(3)(b)1.a.a. If the gross beta particle activity exceeds 50 pCi/L, an analysis of the sample shall be performed to identify the major radioactive constituents present. The appropriate organ and total body doses shall be calculated to determine compliance with sub. (1) (b).

DHS 157.96(3)(b)1.b.b. A supplier of water shall conduct additional monitoring, as required by the department, to determine the concentration of man-made radioactivity in principal watersheds designated by the department.

DHS 157.96(3)(b)1.c.c. At the discretion of the department, a supplier of water utilizing only groundwaters may be required to monitor for man-made radioactivity.

DHS 157.96(3)(b)2.2. After the initial analysis required by subd. 1., a supplier of water shall monitor at least every 4 years following the procedure given in subd. 1.

DHS 157.96(3)(b)3.3. The supplier of any community water system designated by the department as utilizing water subject to contamination by effluents from nuclear facilities shall initiate quarterly monitoring for gross beta particle and iodine-131 radioactivity and annual monitoring for strontium-90 and tritium.

DHS 157.96(3)(b)3.a.a. Quarterly monitoring for gross beta particle activity shall be based on the analysis of monthly samples or the analysis of a composite of 3 monthly samples. If the gross beta particle activity exceeds 50 pCi/L, an analysis of the sample shall be performed to identify the major radioactive constituents present and the appropriate organ and total body doses shall be calculated to determine compliance with sub. (1) (b).

DHS 157.96(3)(b)3.b.b. For iodine-131, a composite of 5 consecutive daily samples shall be analyzed once each calendar quarter. As required by the department, more frequent monitoring shall be conducted when iodine-131 is identified in the finished water.

DHS 157.96(3)(b)3.c.c. Annual monitoring for strontium-90 and tritium shall be conducted by means of the analysis of a composite of 4 consecutive quarterly samples or analysis of 4 quarterly samples.

DHS 157.96(3)(b)3.d.d. Data obtained by the direct monitoring of water supplies in the areas surrounding nuclear facilities may be utilized by the supplier where the department determines such data is applicable to a particular community water system.

DHS 157.96(3)(b)4.4. If the average annual maximum contaminant level for man-made radioactivity specified in sub. (1) (b) is exceeded, the operator of a community water system shall give notice to the department under sub. (7) and to the public as required by sub. (8). Monitoring at monthly intervals shall be continued until the concentration no longer exceeds the maximum contaminant level or until a monitoring schedule as a condition to a variance, exemption or enforcement action becomes effective.

DHS 157.96(4)(4) Alternative analytical techniques. With the written permission of the department concurred in by the administrator of the U.S. environmental protection agency, an alternative analytical technique may be employed. An alternative technique shall be acceptable only if it is substantially equivalent to the prescribed test in sub. (1) in both precision and accuracy as it relates to the determination of compliance with any maximum contaminant level. The use of the alternative analytical technique may not decrease the frequency of monitoring required by sub. (3).