(1) The time requirements of this section shall apply to all substantial development permits and to any development authorized pursuant to a variance or conditional use permit authorized by this chapter. Upon a finding of good cause, based on the requirements and circumstances of the project proposed and consistent with the policy and provisions of the master program and this chapter, local government may adopt different time limits from those set forth in subsections (2) and (3) of this section as a part of action on a substantial development permit.

(2) Construction activities shall be commenced or, where no construction activities are involved, the use or activity shall be commenced within two years of the effective date of a substantial development permit. However, local government may authorize a single extension for a period not to exceed one year based on reasonable factors, if a request for extension has been filed before the expiration date and notice of the proposed extension is given to parties of record on the substantial development permit and to the department.

(3) Authorization to conduct development activities shall terminate five years after the effective date of a substantial development permit. However, local government may authorize a single extension for a period not to exceed one year based on reasonable factors, if a request for extension has been filed before the expiration date and notice of the proposed extension is given to parties of record and to the department.

(4) The effective date of a substantial development permit shall be the date of filing as provided in RCW 90.58.140(6). The permit time periods in subsections (2) and (3) of this section do not include the time during which a use or activity was not actually pursued due to the pendency of administrative appeals or legal actions or due to the need to obtain any other government permits and approvals for the development that authorize the development to proceed, including all reasonably related administrative or legal actions on any such permits or approvals.

(5) Revisions to permits under WAC 173-27-100 may be authorized after original permit authorization has expired: Provided, That this procedure shall not be used to extend the original permit time requirements or to authorize substantial development after the time limits of the original permit.

(6) Local government shall notify the department in writing of any change to the effective date of a permit, as authorized by this section, with an explanation of the basis for approval of the change. Any change to the time limits of a permit other than those authorized by RCW 90.58.143 as amended shall require a new permit application.