The California Department of Motor Vehicles states that financial responsibility must be obtained and maintained on any vehicle operated or parked on California roadways. So if your car is going to be parked on a public street it would need insurance on it.

The CA Department of Insurance notes that all California drivers and owners must have at least the statutory limits of minimum liability insurance or an approved alternative way to pay for injury or property damage they may cause. Penalties are very severe for non-compliance with this section of the vehicle code.

So as the owner of a vehicle parked on the street you would need insurance on the car and be responsible, through vicarious liability, if someone drove it while it was uninsured. The fact that you are living out of state in Michigan will not make a difference to law enforcement if you allow others to drive an uninsured car that is owed by you.

California law requires vehicles to be currently registered if they are driven, towed, stored, parked on public roads or highways or parked in an off-street public parking facility at any time during the registration period.

If your car becomes inoperable and will not be in any of the places listed above, you can apply for non-operational status on the vehicle and pay a planned non-operation (PNO) fee. Once this status is placed on a vehicle's record, it remains until you decide to operate the vehicle and pay full registration renewal fees. At this time you then may be able to take insurance off the car legally but would need to check with the CA DMV to be certain.

To get the state required California auto insurance on your vehicle follow this link.