Wisconsin Administrative Code
Department of Agriculture, Trade and Consumer Protection
ATCP 20-54 - Agricultural Resource Management
Chapter ATCP 31 - Groundwater protection program

Chapter Ag 161 was renumbered ch. ATCP 31 under s. 13.93(2m) (b) 1, Stats., Register, April, 1993, No. 448.

Prefatory (1) The department of agriculture, trade and consumer protection has authority to regulate fertilizer and pesticide bulk storage under s. 94.645, Stats., and pesticide use under ss. 94.67 through 94.71, Stats. Activities subject to department regulation may, under some circumstances, result in the presence of fertilizer substances or pesticide substances in groundwater. Under ch. 160, Stats., the department of natural resources is required to establish numerical standards, consisting of enforcement standards and preventive action limits, for certain substances in groundwater. If a fertilizer substance or pesticide substance is found in groundwater, the department will consider whether the presence of the fertilizer substance or pesticide substance has resulted from, or may be aggravated by an activity subject to department regulation. If the presence of the fertilizer or pesticide substance has resulted from a violation of an existing statute, rule or order administered by the department, the department may seek appropriate enforcement action against the violator, whether or not the contamination exceeds an enforcement standard or preventive action limit adopted by the department of natural resources. If, at a point of standards application, the concentration of a fertilizer substance or pesticide substance in groundwater attains or exceeds an enforcement standard or preventive action limit, the department may take site-specific regulatory action to prevent further groundwater degradation or restore groundwater quality, whether or not the substance concentration has resulted from a violation of an existing statute, rule or order. Site-specific regulatory action will be consistent with ch. 160, Stats., and this chapter. The department will also adopt substance-specific rules, as appropriate under ss. 94.69, 160.19 and 160.21, Stats., for each pesticide substance for which an enforcement standard and preventive action limit are established by the department of natural resources. Rules may include preventive measures designed to minimize the presence of pesticide substances in groundwater statewide. Rules may also include requirements for the implementation of site-specific regulatory responses under specified conditions.

(2) This chapter establishes certain elements of the department's program for the prevention and control of groundwater contamination where it appears that groundwater contamination has resulted from or may be aggravated by activities subject to department regulation. This chapter includes:

(a) Standards for the collection, handling and analysis of official groundwater samples, to ensure the reliability of sample test results used by the department as a basis for regulatory or enforcement action.

(b) The points of standards application at which concentrations of a fertilizer substance or pesticide substance in groundwater may be measured to determine whether an enforcement standard or preventive action limit has been attained or exceeded. These points of standards application are defined, pursuant to s. 160.21(2), Stats., for activities subject to department regulation.

(c) The preliminary investigative steps to be taken by the department upon receipt of groundwater sample test results which indicate the presence of a fertilizer substance or pesticide substance in Wisconsin groundwater.

(d) The enforcement options which are available to the department if the department finds, upon investigation, that the presence of a fertilizer substance or pesticide substance in groundwater has resulted from a violation of an existing statute, rule or order administered by the department under s. 94.645, Stats., or ss. 94.67 through 94.71, Stats.

(e) The site-specific regulatory options which are available to the department under s. 94.645, Stats., or ss. 94.67 through 94.71, Stats., if, at a point of standards application, the concentration of a fertilizer substance or pesticide substance is found to attain or exceed an enforcement standard or preventive action limit.

(f) The general criteria to be considered by the department in its choice of a site-specific regulatory response, or in the adoption of rules which require non-discretionary site-specific responses under specific conditions.

(g) Requirements and limitations governing the prohibition of pesticide uses, whether by site-specific regulatory responses or by rule.

(h) A commitment to adopt substance-specific rules, as appropriate under ss. 94.69, 160.19 and 160.21, Stats., for each pesticide substance for which an enforcement standard and preventive action limit are adopted by the department of natural resources. Rules may include preventive measures designed to minimize the presence of pesticide substances in groundwater statewide. Rules may also include requirements for the implementation of site-specific regulatory responses under specified conditions.

(3) This chapter does not limit the department's rulemaking authority under ss. 94.645, 94.69, 160.19, or 160.21, Stats. In the exercise of its rulemaking authority, the department may consider any information which may be relevant to the rulemaking proceeding, whether or not the information is derived from Wisconsin groundwater samples. The finding of a fertilizer or pesticide substance in groundwater, at a level which equals or exceeds an enforcement standard or preventive action limit, is not a prerequisite to the exercise of the department's rulemaking authority under ss. 94.645, 94.69, 160.19, or 160.21, Stats.

(4) This chapter does not limit the department in the exercise of any of its statutory authority, where the department determines that the exercise of its authority is necessary to comply with a statutory mandate, or to safeguard the public health, safety or welfare.

(5) General rules governing pesticide use and control are contained in ch. ATCP 29. Rules adopted under s. 94.645, Stats., to regulate fertilizer and pesticide bulk storage are contained in ch. ATCP 33.