Environmental Rules in Portage County, WI (2026)
4 rules for unincorporated Portage County, Wisconsin.
Verified from official government sources
Stormwater Management
Unincorporated Portage County requires a stormwater control plan before a Zoning Permit issues for any accessory building, or combined accessory buildings, exceeding 2,000 square feet. The Planning and Zoning Department reviews and approves the plan, and can also require added screening or setbacks for large accessory structures.
Stormwater Plan Required for Large Sheds in Portage County
Some RestrictionsPortage County Code § 7.1.2(1)(b)4.b
4.Accessory buildings, including private garages and buildings clearly incidental to the residential use of the property, provided, however, that no accessory building may be used as a separate dwelling unit. ... b.Any single accessory building or cumulative total exceeding 2,000 square feet will require submittal of a stormwater control plan to the Planning and Zoning Department for review and...
Erosion Control
Portage County requires a storm water management and erosion-control plan before any major subdivision, county plat, or minor subdivision breaks ground in the unincorporated towns, sealed by a registered professional engineer and built to meet Wisconsin's statewide construction-site standards.
Portage County Construction Erosion Control
Some RestrictionsPortage County Code § 7.4.6(4)(a)
(4)Storm Water Management and Construction Site Erosion Control.(a)General Requirements: A storm water management plan shall be provided by the subdivider, at the determination of the Planning and Zoning Department. ... Storm water management plans shall be submitted over the signature and seal of a registered professional engineer, unless authorized otherwise by the Planning and Zoning Departm...
Flood Zones
Any new construction or substantial improvement Portage County finds sited in a mapped floodplain must be engineered to resist flotation and lateral movement, built of flood-resistant materials, and have its utilities placed to keep water out during a flood, before the county issues a floodplain zoning permit.
Portage County Floodplain Construction Standards
Some RestrictionsPortage County Code § 7.6.2(a)
(a)If a proposed building site is in a flood-plane area, all new construction and substantial improvements shall:1.Be designed and anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;2.Be constructed with flood-resistant materials;3.Be constructed by methods and practices that minimize...
Flood Elevation Requirements
Portage County requires two feet of freeboard above the regional flood elevation before a structure counts as protected, and any new residential construction or substantial improvement in the floodfringe must have its lowest floor built up to that flood protection elevation.
Portage County Base Flood Elevation Freeboard
Some RestrictionsPortage County Code §§ 7.1.6(10), 7.6.4(3)(a)1
Flood protection elevation means an elevation of two feet of freeboard above the water surface profile elevation designated for the regional flood. ... 1.All new construction, including placement of manufactured homes, and substantial improvement of residential structures, shall have the lowest floor elevated to or above the flood protection elevation on fill. The fill around the structure shal...
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