The laws of the state of Washington and the provisions of this chapter shall be applicable to all local improvements and proceedings therein initiated by petition or resolution subsequent to the passage and legal publication of this chapter; and all proceedings and the manner of the collection and enforcement of all assessments in such proceedings shall be in compliance therewith; this chapter shall not apply to any local improvement initiated prior to the passage and legal publication of this chapter; all local improvements initiated prior to the passage and legal publication of this chapter shall be completed in accordance with and the collection and delinquency of all assessments now levied or which may hereafter be levied therefor shall be governed by the ordinances and laws of the State of Washington in force at the time of the initiation of such improvement proceedings.