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Sanitary Sewer Service Area Planning

As part of its regional water quality management planning function, the Commission works with local wastewater treatment plant management agencies and the Wisconsin Department of Natural Resources to prepare and update local sewer service area plans.

Sanitary Sewer and Water Supply Service Areas

The Commission’s regional land use plans have long recommended that the great majority of urban density development be served by both public sanitary sewerage systems and public water supply systems.

As the areawide water quality planning agency, the Commission has the ongoing responsibility to work with Region’s local governments and sewerage agencies and the Wisconsin Department of Natural Resources (WDNR) in fulfilling these planning requirements. In Wisconsin, State-level oversight of sanitary sewerage and water supply services is provided by the WDNR.


Regional Water Management Quality Plan

The Regional Water Management Quality Plan provided initial sanitary sewer service area planning recommendations and guidelines that have been updated by other regional plans, most notably by VISION 2050.

Person holding water quality monitoring device

Two important elements of the Regional Water Management Quality Plan relate to:

  • Recommendations for wastewater treatment plants and their associated wastewater conveyance systems
  • Identifying those areas planned to be tributary to and served by the treatment plants (i.e., sanitary sewer service areas)

Regional Water Quality Planning



Passed in 1972, the Clean Water Act included a requirement for areawide waste treatment management planning. This requirement provided a tool to help address water quality management issues.

In 1974, the State designated the Commission as the areawide water quality planning agency for Southeastern Wisconsin. Later that decade, the State specified that areawide water quality management plans include a sewer service area planning component. Upon approval of these plans by the WDNR, the plans become regulatory documents that constrain State decision-making on locally proposed sanitary sewer extensions.

The Regional Water Management Quality Plan delineated 85 sanitary sewer service areas tributary to each recommended public sewage treatment plant in the Region. Since then, staff has refined and detailed most of these sewer service areas in cooperation with local units of government.


Sanitary Sewer Service Areas

Sanitary sewer service area plans identify the outer boundary of the area within which sanitary sewers may be extended. The plans also identify the extent of environmentally significant areas within each sewer service area where the extension of sewers to serve new “urban” development is not permitted. Within the environmentally significant areas, sewered development is confined to limited recreational and institutional uses and rural-density residential development (maximum of one dwelling unit per five acres) in upland areas.

More information can be found through the following links:

Additional information on sanitary sewer area planning in Wisconsin may be found on the WDNR website.

Drop of water in a lake

Sanitary Sewer Extension Reviews

One of the Commission’s responsibilities as the areawide water quality planning agency is to review public and private sanitary sewer extensions for conformance with the Regional Water Management Quality Plan in general, and with the sanitary sewer service area planning component of that plan in particular.

The findings of these reviews are presented in a letter from the Commission typically referred to as a “208 letter” or “WQM letter.” Detailed information about the submittal requirements for, and the review process of, these letters may be found below.

Sewer Extension Review Guidance


Wastewater Treatment Plant Facilities Planning

The Regional Water Management Quality Plan also provides recommendations for the control of water pollution from point sources as wastewater treatment plants, points of separate and combined sewer overflows, and industrial waste outfalls.

In matters related to these recommendations, and at the request of the WDNR, the Commission reviews and comments on local wastewater facilities plans prepared by the Region’s public or private wastewater treatment plant operators.