Another natural resource that folks love to explore in northern California are hot springs. Like soaking in nature’s own Jacuzzi, you can find hot springs in a variety of locations throughout the state. One of the closest to Sacramento is Harbin Hot Springs.
Located approximately 93 miles northwest of Sacramento in Middletown, California, Harbin Hot Springs is one of the oldest hot springs in the state and is owned by the Heart Consciousness Church, operating as a nonprofit retreat center. The site is clothing-optional, and offers massages, yoga, trail hiking, healthy meals and overnight camping in addition to soaking in 8 different pools.

6-hour day visits cost $20 per person from Monday through Thursday, or $30 per person on weekends and holidays. (Be sure to make reservations online to avoid an additional $5 fee for arriving unannounced.)
For more hot springs locations near Sacramento check out this article from the Sacramento Bee.