Service areas to provide special services within an organized borough may be established, altered, or abolished by the assembly, subject to the provisions of law or charter. A new service area shall not be established if, consistent with the purposes of this article, the new service can be provided by an existing service area, by incorporation as a city, or by annexation to a city. The assembly may authorize the levying of taxes, charges, or assessments within a service area to finance the special services.