Home-based businesses are allowed to operate as offices, professional offices, and offices for financial, insurance, real estate, civic, educational, religious, and philanthropic organizations, whether for single or multiple occupancy. A home-based business is any business operated in a residential dwelling that manufactures, provides, or sells goods or services and that is owned and operated by the owner or tenant of the residential dwelling. However, use of a home-business may be restricted by any deed, covenant, or agreement restricting the use of land. All buildings must function as home office buildings, and individuals may maintain an office or conduct a customary home occupation within their private residence. This is permitted as long as there are no extensions or modifications that alter the outward appearance of the dwelling, and there is no outward evidence of the business other than a single, non-illuminated sign that does not exceed one square foot in area, attached flat against the building.