Wastewater_Content Page_Statewide Phosphorus Multidischarger Variance

Statewide Phosphorus Multi-Discharger Variance

The multi-discharger variance (MDV) for phosphorus extends the timeline for complying with low-level phosphorus limits. In exchange, point sources commit to step-wise reductions of phosphorus within their effluent as well as helping to address nonpoint sources of phosphorus from farm fields or other agricultural sites by implementing projects designed to improve water quality. The MDV is similar to an individual variance. However, multiple point sources can be covered under the MDV, whereas an individual variance only applies to a single facility. This provides for administrative streamlining and maximizes the potential benefits watershed projects may have through the variance program. The MDV factsheet [PDF] provides general information regarding this program. The Wisconsin Department of Natural Resources (DNR)'s Program Policy for Implementing Wisconsin's Multi-Discharger Variance [PDF] provides details about eligibility and implementation requirements for this program.

MDV Reauthorization

Wisconsin's phosphorus MDV was initially approved by the Environmental Protection Agency (EPA) on Feb. 6, 2017. Throughout 2023 and 2024, DNR and the Wisconsin Department of Administration (DOA) worked with stakeholders and EPA to extend the duration of the MDV. On September 3, 2025 EPA issued a reauthorization, extending the MDV’s availability to September of 2035. 

Phosphorus Variance Package Available for Download:

Webinar recording

Learn about eligibility and process to achieve successful approval of a multi-discharge phosphorus variance.