This chapter applies to all swimming pools and spas owned or operated by local or state government, or commercial interests or private entities including but not limited to facilities operated by cities, counties, public or private school corporations, hotels, motels, camps, apartments, condominiums, and health or country clubs. This chapter does not apply to facilities intended for single family use or to a swimming pool or spa operated by a homeowners’ association representing seventy-two or fewer dwelling units if the association’s bylaws, which also apply to a rental agreement relative to any of the dwelling units, include an exemption from the requirements of this chapter, provide for inspection of the swimming pool or spa by an entity other than the department or local board of health, and assume any liability associated with operation of the swimming pool or spa. This chapter does not apply to a swimming pool or spa used exclusively for therapy under the direct supervision of qualified medical personnel. To avoid duplication and promote coordination of inspection activities, the department may enter into written agreements with a local board of health to provide for inspection and enforcement in accordance with this chapter.