My 17 year old wants to move out before he turns 18 (Nov 2026). I have questions regarding this issue

Until your child turns 18, as his parent, you remain legally responsible for his actions. If he is still in high school after he turns 18, depending upon basic factors, child support will continue until he graduates or turns 19, whichever occurs first. These are two separate concepts.  

A 17-year-old is still a minor until his 18th birthday. California Family Code section 6500 defines a minor as a person under 18, and Family Code section 3010 gives parents custody rights over an unemancipated minor child. Parent authority generally ends when the child reaches majority, marries, is emancipated, or a guardian is appointed.

So, before he turns 18, the parent can legally require him to live at home unless there is emancipation, a guardianship, a dependency/juvenile court order, or another lawful placement. But after he turns 18, the parent cannot legally force him to remain in the home merely because he has not yet graduated.

The parent can lawfully insist that he live at home, can refuse consent to his living elsewhere, can report him missing/runaway if he leaves, and can involve law enforcement or probation/juvenile resources if he is beyond parental control. Welfare and Institutions Code section 601 gives juvenile court jurisdiction over minors ages 12 through 17 who persistently refuse reasonable parental directions, are beyond parental control, or are habitually truant.

I suggest you document that the home remains available, safe, and appropriate; that the parent is willing to provide food, shelter, clothing, schooling support, and medical care; and that you do not consent to an unauthorized move before age 18. If there is an existing custody/support order and the child actually changes residence, file promptly to clarify custody, redirect or modify support, and prevent arrears from accruing under an outdated factual premise