After any Algicide Permit is issued, and before the permit expires, if there is any major change either in the operation of the community water supply or in algae growth that affects the use of the algicide, copper sulfate, copper sulfate based products, or copper sulfate chemical aids, as outlined in the permit, the community water supply must submit an application for modification of its permit. This application must contain all the information required by Section 602.405.
Ill. Admin. Code tit. 35, § 602.415