(a) The following activities are deemed by the department to be Type II actions under SEQRA and its implementing regulations, and the department shall not require an environmental impact statement or any other determination or procedure under SEQRA for these activities:

1. (1) Installation of a new individual sewage treatment system on an individual lot which is not within a subdivision, or within a subdivision which has been approved as of the effective date of these rules and regulations.
2. (2) Any alteration or modification of an existing individual sewage treatment system.