(1) The owner or operator of a compost facility subject to the provisions of ARM Title 17, chapter 50, subchapter 13, shall conduct post-closure care and maintenance for two years, or a longer period as the department determines necessary to protect human health or the environment. During the post-closure care period, the owner or operator shall:

(a) continue to monitor and sample ground water or surface water, if applicable; and

(b) inspect and maintain any cover material or vegetation.