The new bond is designed to provide funding for more than US$7.5bn (£4.3bn) of projects.
"Water is the lifeblood of any civilisation and for California it's the precondition of healthy rivers, valleys, farms and a strong economy," said Governor Edmund Brown. "With this water bond, legislators from both parties have affirmed their faith in California's future."
The new bond includes US$7.12bn in new debt, plus the repurposing of existing unspent bond funds of US$425m for a total of US$7.545bn. None of the repurposed funds will be taken from existing projects.
The funding will be used for water use efficiency and recycling, groundwater clean-up and management, with US$2.7bn allocated for additional water storage. It invests in safe drinking water, particularly in disadvantaged communities, and provides for watershed restoration and increased flows in some of California's most important rivers and streams.