NR 110.15(3)(a)2.2. Any sewage treatment facility located in a floodplain, or suspected to be in a floodplain, will not be approved until the flood analysis requirements of s. NR 110.09 (2) (n) are met. NR 110.15(3)(a)4.4. All sewage treatment facilities which are located in a floodplain shall be floodproofed to an elevation of at least 2 feet above the regional flood elevation. NR 110.15(3)(a)5.5. Location of a land disposal system in a floodplain will be evaluated on a case-by-case basis. NR 110.15(3)(b)1.1. No new sewage treatment facility shall be located in a floodway as defined in ss. NR 116.03 and 116.11. A change in the zoning classification of a treatment facility site from floodway to flood fringe in accordance with the procedures specified in s. NR 116.21 (6), will be acceptable only if the rezoning is complemented by the construction of a dry land access as defined in par. (c). When the facility site is rezoned from floodway to flood fringe, the dry land access requirement will not be waived. NR 110.15(3)(b)2.2. Any existing sewage treatment facility which is located in a floodway shall meet the requirements of subd. 1. if the expansion or upgrading of the facility is greater than 50% of the value of the facility. Value is defined in par. (c). NR 110.15(3)(b)3.3. Any existing sewage treatment facility which is located in a floodway will not have to comply with the requirements of subd. 1. if the expansion or upgrading of the facility is less than 50% of the value of the facility. In this instance, the dry land access requirements of par. (c) will not apply. NR 110.15(3)(c)1.1. Sewage treatment facilities shall be accessible at all times. Sewage treatment facilities located in a flood fringe shall be accessible by dry land access. Dry land access is defined as a service road which has a minimum elevation of at least one foot above the regional flood elevation. NR 110.15(3)(c)2.2. The dry land access requirement may be waived by the department if one of the following criteria is met: NR 110.15(3)(c)2.a.a. The physical characteristics of the treatment site and the surrounding area pose practical difficulties for construction of dry land access, and the isolation of the sewage treatment facility during the regional flood is less than 24 hours for mechanical treatment facilities, or 5 days for lagoon systems. The duration of the regional flood shall be calculated using the methods described in s. NR 116.07; or NR 110.15(3)(c)2.b.b. The physical characteristics of the treatment site and the surrounding area pose practical difficulties for construction of dry land access, and the treatment facility access is inundated by less than one foot of water during the regional flood. In these instances, the access roads shall be stabilized and delineated; or NR 110.15(3)(c)2.c.c. The construction costs of the expansion or upgrading of an existing treatment facility are less than 50% of the value of the existing facility. The value of the existing facility shall be calculated by subtracting the 20-year total present worth of expanding or upgrading the existing facility from the 20-year total present worth of the most cost-effective treatment alternative located at another site which is not in a floodplain. NR 110.15(3)(d)1.1. In order to minimize any potential odor, noise, and nuisances caused by sewage treatment facilities, and to enhance plant security and reliability, sewage treatment facilities shall be isolated from commercial establishments and from buildings occupied or intended for residential use, and from land which is actively being developed for commercial or residential use. The following separation distances shall be maintained: NR 110.15(3)(d)1.a.a. 150 meters (500 feet) for mechanical treatment facilities, effluent holding and polishing ponds; NR 110.15(3)(d)1.b.b. 150 meters (500 feet) for seepage cells, ridge and furrow systems, and overland flow systems; NR 110.15(3)(d)1.d.d. 305 meters (1,000 feet) for off site sludge holding facilities and spray irrigation systems; and NR 110.15(3)(d)2.2. The department may waive the requirements of subd. 1. if the requirements prevent implementation of the cost-effective treatment alternative at an existing sewage treatment facility site. When a waiver is requested, the owner shall demonstrate to the department that: NR 110.15(3)(d)2.a.a. The owner has made reasonable attempts to obtain an agreement from any affected property owner which states that the property owner has been informed of the potential nuisances which may result from the operation of the sewage treatment facilities and that the property owner does not object to the construction and operation of the sewage treatment facilities; and NR 110.15(3)(d)2.b.b. The treatment facility owner has enacted a zoning ordinance which prohibits future construction within the applicable separation distances, or has purchased sufficient land surrounding the sewage treatment facility to prevent future encroachment. NR 110.15(3)(d)3.3. The department may waive the requirements of subd. 1. if the requirements prevent construction of the cost-effective treatment alternative at a new site. When a waiver is requested the owner shall demonstrate that: NR 110.15(3)(d)3.a.a. The treatment facility has obtained from the affected property owners the agreements described in subd. 2. a. or that the proposed sewage treatment facility site is the only reasonably available site or, the costs associated with using another site would place an unreasonable or excessive financial burden on the community; and NR 110.15(3)(d)3.b.b. The treatment facility owner has enacted a zoning ordinance which prohibits future construction within the applicable separation distances, or has purchased sufficient land surrounding the proposed treatment facility site to prevent future encroachment. NR 110.15(3)(e)(e) Protection of water supply wells. Wastewater lagoons or storage structures shall be located with a minimum separation distance of 1,000 feet from a community water system well, and 100 feet from a private water system well or any other well subject to ch. NR 812. Wastewater treatment plant effluent pipes shall be located with a minimum separation distance of 50 feet from a private water system well or any other well subject to ch. NR 812.