Section 8Local Government Code of 1991 (Republic Act No. 7160), Sec. 8

Division and Merger. - Division and merger of existing local government units shall comply with the same requirements herein prescribed for their creation: Provided, however, That such division shall not reduce the income, population, or land area of the local government unit or units concerned to less than the minimum requirements prescribed in this Code: Provided, further, That the income classification of the original local government unit or units shall not fall below its current classification prior to such division.

The income classification of local government units shall be updated within six (6) months from the effectivity of this Code to reflect the changes in their financial position resulting from the increased revenues as provided herein.