641—158.1 (125) Service areas established. The department of public health has established regions for substance abuse prevention and treatment service areas. Substance abuse assessment, prevention and education, and outpatient and follow-up treatment and rehabilitation shall be available in each service area. Emergency treatment provided by a facility affiliated with or part of the medical service of a general hospital, inpatient treatment, residential treatment, and halfway house treatment shall be available within reasonable driving distance of the service area.