To fund a single-payer health care system, California Democratic lawmakers have proposed a constitutional amendment that would nearly double the states’ tax revenue.  If enacted, it will increase the top marginal income-tax rate to 18.05 percent from the current 13.3 percent for individuals, and businesses will be subject to gross receipt tax of 2.3 percent on their revenue in addition to 8.84 percent corporate income tax.  The combined marginal tax rate for top income earners would rise to 57.65 percent (39.6% for federal plus 18.05% for California).

Both the California State Senate and Assembly would need to vote in favor by a 2/3 majority to pass the proposal.  Currently, the Democrats have 75 percent sittings in both houses, and it may very well happen.  Price of living in the Golden State is becoming unaffordable for many people.  Please see the article published by Tax Foundation for further detail (a link provided below).

https://taxfoundation.org/california-health-care-tax-proposal/