The city shall further require that all such streets, avenues, alleys and/or utility easements as referred to in section 1-11-4 of this chapter be surveyed, brought to proper grade, curbs and gutters installed, proper base material installed and surfaced in accordance with existing city specifications. All water and sewer lines must be extended using appropriate sized pipes to meet the needs of the development and as required by city specifications. All street, avenue and alley extensions, curbs and gutters and utility extensions are to be done at the sole expense of the owner(s) of the property to be annexed. (1975 Code § 2.60.050)