(a) Description. The Seashore District shall include all those portions of the towns of Provincetown, Truro, Wellfleet, Eastham, Orleans and Chatham lying within the exterior boundaries of the Cape Cod National Seashore.

(b) Zoning bylaws for the Seashore District shall be consistent with the objectives and purposes of the Act of August 7, 1961, so that—to the extent possible under Massachusetts law—the scenic, scientific and cultural values of the area will be protected, undeveloped areas will be preserved in a natural condition, and the distinctive Cape Cod character of existing residential structures will be maintained.

(c)(1) No moving, alteration, or enlargement of existing one-family residential dwellings or structures accessory thereto situated within this District shall be permitted if such would afford less than a 50-foot setback from all streets measured at a right angle with the street line, and a 25-foot distance from the abutters' property lines (or less than such lesser setback or distance requirements already in existence for such dwellings or accessory structures).

(2) If through natural phenomena or causes a lot or lots are so diminished in size that an owner would be unable to comply with the setback or sideline requirements herein prescribed, such owner or the zoning authorities may, as provided in § 27.4(b), request the Secretary of the Interior to determine whether a proposed move, reconstruction, alteration of enlargement of an existing residential dwelling or accessory structure would subject the property to acquisition by condemnation.

(d) Zoning bylaws adopted pursuant to this regulation shall contain provisions designed to preserve the seashore character of the area by appropriate restrictions or prohibitions upon the burning of cover, cutting of timber, filling of land, removal of soil, loam, sand or gravel and dumping, storage, or piling of refuse and other unsightly objects or other uses which would detract from the natural or traditional seashore scene.

(e) Zoning bylaws for the Seashore District may permit residential uses of “improved property” and other uses of such dwellings and their accessory structures: Provided, Such other uses are traditional to these seashore communities, are customarily incidental to the principal residential use and do not alter the essential character of the dwelling and premises as a private residence. Subject to those conditions such uses may include, but are not limited to: (1) Partial use of dwellings by residents for a professional office (as for the practice of theology, law or medicine), as an artists' studio, for appropriate small scale home occupations as the making and selling of traditional Cape Cod products produced on the premises, and for the rental of rooms and serving of meals by residents of the premises to overnight guests; (2) the existence of structures, such as a garage, barn or boathouse accessory to the dwelling; (3) display of a sign which may be indirectly but not directly illuminated and not to exceed two square feet in area, referring to the occupancy, sale, or rental of the premises; (4) traditional agricultural uses of cleared land, but not including such objectionable uses as a piggery or the raising of livestock, poultry or fur-bearing animals for commercial purposes; and (5) the opening of shellfish, the storage and use of fishing equipment, and other traditional fishing activities. No commercial or industrial ventures (other than of the types described above), may be established within the Seashore District.