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Proposed Wisconsin Phosphorus Rule (CR10-035)

Most Recent Action

The EPA has approved the rule. July 2012.



In 2000, the EPA promulgated nutrient criteria guidance for both lakes and streams and set a promulgation deadline of the end of 2004. Under s. 303(c)(4)(B) of the Clean Water Act, the EPA may determine, in the absence of state adopted criteria, that a new or revised standard is needed to meet Clean Water Act requirements and may promulgate criteria for the state. On November 23, 2009, seven groups notified EPA of their intent to sue over the EPA’s failure to promulgate phosphorus and nitrogen criteria for Wisconsin.

The Wisconsin DNR revisised Chapters NR 102 and NR 217 of the Wisconsin Administrative Code relating to phosphorus water quality standards criteria and limitations and effluent standards. The Natural Resources Board adopted the rule at its June 2010 meeting.



Section 227.11(2)(a), Stats., expressly confers rulemaking authority on the department to promulgate rules interpreting any statute enforced or administered by it, if the agency considers it necessary to effectuate the purpose of the statute.

The phosphorus water quality standard included in the rule is required pursuant to s. 281.15, Stats., which directs the department to promulgate water quality standards for state waters.

Section 283.13 (5), Stats., gives the department the authority to establish water quality based effluent limitations based on applicable water quality standards and to require compliance with those limitations consistent with a schedule of compliance or state or federal law.

Section 283.15, Stats., provides authority to establish rules for variances to water quality standards, s. 283.31, Stats., provides authority to establish permit terms and conditions for water pollutant discharge elimination system permits, and s. 283.37, Stats., gives the department authority to require the submittal of information as part of a permit application.



The rule has two parts. The first is a set of phosphorus water quality standards criteria for rivers, streams, various types of lakes, reservoirs and Great Lakes. The second is procedures for determining and incorporating phosphorus water quality based effluent limitations into Wisconsin Discharge Pollutant Elimination System (WPDES) permits under chapter 283, Stats.

These standards are the most restrictive in the Midwest. Compliance costs are estimated at $1.13 billion to $4 billion.


Phosphorus Water Quality Standards Criteria

Below is a table showing the phosphorus water quality standards criteria by type of water body. The specific water body types are defined in the proposed rules, and there are some exclusions based on size or flow conditions.


Type of Water Body Total Phosphorus in ug/l
Listed rivers 100
All other streams 75
Stratified reservoirs 30
Non-stratified reservoirs 40
Stratified “two-story” fishery lakes 15
Non-stratified (shallow) drainage lakes 40
Stratified seepage lakes 20
Non-stratified (shallow) lakes 40
Stratified seepage lakes 20
Non-stratified (shallow) lakes 40
Impoundments Same as inflowing river or stream
Lake Michigan open and nearshore waters 7
Lake Superior open and nearshore waters 5


WPDES Effluent Standards and Limitations

The rule includes provisions for determining when a water quality based effluent limitation is needed in a WPDES permit; equations and procedures for calculating effluent limits based on different types of waters and stream flow assumptions; and provisions for expressing permit compliance averaging periods, such as a monthly average. The rule requires concentration limits, and specifies where and how mass limits are required. The rule also addresses the relationship and procedures for including a various types of phosphorus limits in permits such as a phosphorus limit based on a total maximum daily load, a technology based phosphorus limit and a water quality based phosphorus limit calculated under the new procedures in chapter NR 217.

The rule allows the DNR to include compliance schedules in permits. The compliance schedule provisions specify factors the department may consider when establishing the length of a compliance schedule. One of the options for a compliance schedule provision for discharges to nonpoint source dominated waters includes an adaptive management option where interim limits may be phased in, if phosphorus concentrations improve in the receiving water.

There are also provisions for a streamlined approach for processing variances for stabilization pond and lagoon systems.


Related Documents

Statement of Scope

Initial Proposed Rulemaking Order

Fiscal Estimate

Report to Legislative Council Rules Clearinghouse

Clearinghouse Review of Rule

Final Rulemaking Order

EPA Approval of the Rule

DNR’s Phosphorous Website