Transit, Roundabout, Trail
Transit, Roundabout, Trail

Example of an environmentally sensitive area (ESA). A stream is buffered by undeveloped land to either side.

What is an ESA? 

An ESA, or Environmentally Sensitive Area, is a landscape feature identified in a Sewer Service Area Plan due to its role in maintaining and protecting water quality. ESAs, which may include waterways, wetlands, sloping land, Karst features, floodways, and setback areas, are prohibited from development to ensure local water quality is maintained. ESAs and ESA setbacks are not buildable areas. Development and earth moving activities should not occur within ESAs or ESA buffers. 

Can I change an ESA boundary on my property?

ESAs are identified, mapped, and published online to provide notice to communities, the public, and developers of areas prohibited from public sewer development.  Properties purchased after the delineation of an ESA (displayed on the property’s plat map) should be maintained. Questions involving acceptable activities within and near an ESA can be directed to the Brown County SSA Plan Contact Devin Yoder at

Unique circumstances may arise in which an applicant wishes to petition for an amendment to the Wisconsin DNR for an ESA modification.  While this process is discouraged, the Brown County Sewerage Plan provides directions on requesting such a change. The amendment must be approved by Brown County Planning staff, the Brown County Planning Commission Board of Directors, and Wisconsin DNR. 

Legal Background

The indentification and protection of ESA's begins with the Areawide Water Quality Management Plan.  The Areawide Water Quality Management Plan is a requirement under Wisconsin Administrative Code NR 121.  Through an agreement with the Department of Natural Resources, Brown County Planning Commission was designated as the Areawide Water Qualtiy Management Agency that would administer the Areawide Water Qualtiy Management Plan (Brown County Sewage Plan) and thereby protect the designated ESA's.
ESA's Defined

NR121.05(1)(g)2c defines environmentally sensitive areas as: "major areas unsuitable for the installation of waste treatment systems because of physical or environmental constraints are to be excluded from the service area. Areas considered for exclusion from sewer service areas due to potential adverse impacts on water quality from both point or nonpoint source pollution include (but are not limited to) wetlands, shorelands, floodways and floodplains, steep slopes, highly erodible soils and other limiting soil types, groundwater recharge areas, and other such physical constraints."

ESAs are defined in the SSA plan, along with the rules and procedures for identifying necessary protections such as setbacks and stormwater/groundwater or related water management actions. A sewer service area plan outlines sewer service for 20 year time horizons. Environmentally sensitive areas should be determined with the aid of the following sources:
ESA's and the Brown County Land Division and Subdivision Ordinance

In an effort to be more proactive in protecting ESAs defined by NR 121 and adopted witihin the Brown County Sewage Plan, Brown County Planning incorporated the same ESA language and protective areas (setbacks) as elements of land division reviews.  This effort makes property owners and developers aware of areas that are not able to be disturbed near the begining of a project timeline so that building and site layouts can be planned accordingly.
ESA Amendments
Additional Information on Sewer Service Area Planning and Environmentally Sensitive Areas