How many months in California triggers the presumption of residency according to California tax law?

In California tax law, an individual is presumed to be a resident if they are present in the state for more than nine months during the year. This presumption is significant as it establishes residency for tax purposes, meaning that all income earned can be subject to California state taxation. The reasoning behind this nine-month threshold is based on the state’s interest in ensuring that those who are residing in California for a substantial part of the year contribute to the state's revenue through taxes.

Individuals who are in California for a shorter duration may not meet this threshold and could qualify as non-resident taxpayers, who are only taxed on income sourced from California. This distinction is crucial for tax planning and compliance, as it can greatly affect one’s tax obligations and benefits in the state.

This nine-month criterion aligns with similar residency laws in other jurisdictions, emphasizing a practical approach to defining residency based on time spent physically present in the state.