No modifications or additions to a nonconforming use or structure
shall be permitted unless they comply with this chapter. The words
"modification" and "addition" include, but are not limited to, any
alteration, addition, modification, rebuilding or replacement of any
such existing use, structure or accessory structure or use. Maintenance
is not considered a modification; this includes painting, decorating,
paneling and the replacement of doors, windows and other nonstructural
components and the maintenance, repair or replacement of existing
private sewage or water supply systems or connections to public utilities.
Any costs associated with the repair of a damaged structure are not
considered maintenance.