Serenity Knolls: Chemical Dependency Recovery Program [1] Primary Focus: Mix of mental health and substance abuse services. Type of Care: Residential short-term treatment (30 days or less), Residential long-term treatment (more than 30 days). Phone: (415) 488-0400Email: [2]Address: P.O. Box 640 Forest Knolls, CA 94933 Fees: Self payment