Section NR 118.08 - Nonconforming uses and structures and substandard lots(1) NONCONFORMING USES. A nonconforming use may not be expanded or enlarged. An increase in the volume, intensity or frequency of use is allowed if the area used for the nonconforming use is not enlarged. A change from one nonconforming use to another nonconforming use is not allowed. If a nonconforming use is discontinued for a period of 12 months, any future use of the building and premises shall conform to all of the requirements of the local zoning ordinance.(2) NONCONFORMING PRINCIPAL STRUCTURES. In all management zones, ordinary maintenance and repair of nonconforming principal structures is allowed. However, structural alteration, reconstruction and expansion of nonconforming principal structures and replacement, improvement or structural alteration of the foundation may only be allowed if all of the following requirements are met, where applicable: (a)Reconstruction of nonconforming principal structures. Nonconforming principal structures located within the ordinary high water mark setback area, bluffline setback area or slope preservation zone may be structurally altered or reconstructed and foundations may be replaced, improved or structurally altered if all of the following requirements are met:1. The lot has an area of at least 7,000 square feet.2. The altered or reconstructed structure will be visually inconspicuous or will be rendered so through mitigation in accordance with sub. (5).3. The structure is altered or reconstructed in the same footprint as the pre-existing structure.4. The height of the altered or reconstructed structure complies with s. NR 118.06(1) (d). The reconstructed structure may not be any taller than the pre-existing nonconforming structure, except that a flat roof may be replaced with a pitched roof.5. The color of the structure complies with s. NR 118.06(2).6. The property owner submits a mitigation plan that complies with the requirements of sub. (5). If a permit is issued for the reconstruction, the mitigation plan shall be approved, or modified and approved, by the local zoning authority. The mitigation plan shall be incorporated into the permit and the property owner shall be required to implement the mitigation plan as a permit condition.7. Private on-site wastewater treatment systems are brought into compliance with the requirements of ch. SPS 383.8. The foundation of the structure may not be replaced, improved or structurally altered. Notwithstanding the definition of "reconstruction" in s. NR 118.03(36) and the preceding sentence, the foundation of the structure may be replaced, improved or structurally altered in conjunction with the reconstruction of the structure if the entire structure is more than 50 feet from the ordinary high water mark and is not located in a slope preservation zone.9. An erosion control plan and revegetation plan shall be submitted to the local zoning authority for approval, or modification and approval, prior to the issuance of a permit for the structural alteration or reconstruction.10. There will be no filling and grading activities conducted during the alteration or reconstruction, except for the minimum necessary to accomplish the alteration or reconstruction in compliance with other provisions of this chapter, and as needed to upgrade a private on-site wastewater treatment system, to replace sewer or water laterals, or to install storm water or erosion control measures.11. If the nonconforming principal residence is located in a slope preservation zone, it may be reconstructed only if Wisconsin construction site best management practices applicable to steeper sloped areas are implemented to control erosion. Note: Approved best management practices for construction site erosion control can be found in Wisconsin's Construction Site Best Management Practice Handbook (WDNR Pub. WR-222 November 1993 Revision) which is available from the Wisconsin Department of Administration, Document Sales, 4622 University Avenue, Madison, WI 53705-2156.
(b)Expansion of nonconforming principal structures. Nonconforming principal structures located in the ordinary high water mark setback area or bluffline setback area may be expanded and the pre-existing foundation may be replaced, repaired or structurally altered in conjunction with the expansion if all of the applicable following requirements are met:1. Structures located wholly or partially within 50 feet of the ordinary high water mark may not be expanded.2. Structures located wholly or partially within slope preservation zones may not be expanded.3. Structures entirely set back more than 50 feet from the ordinary high water mark but located wholly or partially less than 75 feet from the ordinary high water mark may be expanded only if there is no compliant building location available on the lot.4. Structures entirely set back more than 75 feet from the ordinary high water mark may be expanded regardless of whether a compliant building location exists elsewhere on the lot.5. The lot has an area of at least 7,000 square feet.6. The expanded structure will be visually inconspicuous or will be rendered so through mitigation.7. Any reconstructed portion of the nonconforming structure may only be reconstructed in the same footprint as the pre-existing structure. Notwithstanding the definition of "reconstruction" in s. NR 118.03(36), the pre-existing foundation of a structure that is more than 50 feet from the ordinary high water mark and is not within a slope preservation zone may be replaced, repaired or structurally altered in conjunction with the expansion of the structure.8. For structures located wholly or partially within the ordinary high water mark setback area, the total footprint of the structure may not exceed 1500 square feet.9. For structures located wholly or partially within the bluffline setback, but not within the ordinary high water mark setback area, the total footprint of the structure may not exceed 2000 square feet and the structure shall comply with all of the requirements in s. NR 118.06(1) (f) 4.10. Expansion is on the side of the structure farthest from the river or, if landward expansion is not possible, the expansion is parallel to the ordinary high water mark or bluffline.11. The height of the structure complies with s. NR 118.06(1) (d).12. The color of the structure complies with s. NR 118.06(2).13. The property owner submits a mitigation plan that complies with the requirements of sub. (5). If a permit is issued after a mitigation plan is approved, or modified and approved, by the local zoning authority, the mitigation plan shall be incorporated into the permit and the property owner shall be required to implement the mitigation plan as a permit condition.14. Private on-site wastewater treatment systems are brought into compliance with the requirements of ch. SPS 383.15. An erosion control plan and revegetation plan shall be submitted to the local zoning authority for approval, or modification and approval, prior to the issuance of a permit for the expansion.16. There will be no filling or grading conducted as part of the reconstruction or expansion except as necessary to reconstruct or build the expansion in compliance with other provisions of this chapter, upgrade a private on-site wastewater treatment system, replace sewer or water laterals, or install storm water or erosion control measures.(3) NONCONFORMING ACCESSORY STRUCTURES. In all management zones, ordinary maintenance and repair of nonconforming accessory structures is allowed. Nonconforming accessory structures may not be structurally altered, reconstructed or expanded, except that garages and storage sheds may be structurally altered, reconstructed or expanded if all of the following requirements are met where applicable:(a) The entire garage or storage shed is not located in a slope preservation zone.(b) The entire garage or storage shed is set back more than 75 feet from the ordinary high water mark.(c) The garage or storage shed is not used for human habitation.(d) The total footprint of all nonconforming accessory structures, other than existing driveways, within 75 feet of the ordinary high water mark, within a slope preservation zone or within the bluffline setback area may not exceed 500 square feet.(e) The garage or storage shed is built with earth-tone building materials that are non-reflective, except that windows may be made of ordinary window glass or non-reflective glass, but may not be made of glass designed to reflect more light than ordinary window glass.(f) Mitigation measures are implemented and maintained that comply with the requirements of sub. (5).(g) The structure is visually inconspicuous or will be rendered so through a mitigation plan that complies with sub. (5).(4) SUBSTANDARD LOTS. Lots of record in the register of deeds office on January 1, 1976, or on the date of the adoption of an amendment to a riverway ordinance that makes a lot substandard, which do not meet the requirements of this chapter, may be allowed as building sites provided that the following criteria are met: (a)1. The lot is in separate ownership from abutting lands, or2. The lot by itself or in combination with an adjacent lot or lots under common ownership in an existing subdivision has at least one acre of net project area. Adjacent substandard lots in common ownership may only be sold or developed as separate lots if each of the lots has at least one acre of net project area.(b) All structures that are proposed to be constructed or placed on the lot and the proposed use of the lot comply with the requirements of the local unit of government's Lower St. Croix riverway ordinance and any underlying zoning or sanitary code requirements.(5) MITIGATION REQUIREMENTS. Expansion or reconstruction of nonconforming principal structures, and the expansion, reconstruction or structural alteration of nonconforming accessory structures shall trigger mitigation requirements to offset the impacts of the proposed project. Mitigation measures shall be roughly proportional to the magnitude of the impacts of the proposed project on scenic resources, water quality, erosion potential and the protection of the shoreland area. Mitigation shall include, but may not be limited to, the following: (a) Planting trees capable of screening the entire structure, if existing vegetation is not sufficient to render the structure visually inconspicuous. The trees shall be native to the area, at least 2 inches diameter breast height and planted no more than 12 feet apart.(b) The vegetation in the area within 50 feet of the ordinary high water mark shall be preserved or restored through planting of native vegetation. Vegetation shall be established or maintained at densities that are adequate to protect water quality, habitat and natural scenic beauty of the shoreland area. If a nonconforming structure is located in this area, the vegetation shall be planted surrounding the structure, although the owner may create a screened view of the river from the structure and may leave a 15-foot wide mowed area around the structure to protect it from wildfire.(c) Best management practices shall be followed to encourage stormwater infiltration and to limit erosion and runoff. Note: Approved best management practices for construction site erosion control can be found in Wisconsin's Construction Site Best Management Practice Handbook (WDNR Pub. WR-222 November 1993 Revision) which is available from the Wisconsin Department of Administration, Document Sales, 4622 University Avenue, Madison, WI 53705-2156.
(d) An affidavit describing the approved mitigation plan shall be executed and recorded with the county register of deeds by the property owner within 14 days after approval of the mitigation plan. The affidavit shall alert subsequent purchasers of the land of the requirements of the mitigation plan.Wis. Admin. Code Department of Natural Resources § NR 118.08
CR 03-054: cr. Register October 2004 No. 586, eff. 11-1-04; correction in (2) (a) 7., (b) 14. made under s. 13.92(4) (b) 7, Stats., Register February 2012 No. 674.