The department's update comes one day after the Centers for Disease Control and Prevention (CDC) changed its mask guidance in response to the rise in coronavirus cases.
The CDC has called for all vaccinated people in high-transmission areas to wear a mask indoors, reinstating previous pandemic restrictions.
"The Delta variant has caused a sharp increase in hospitalizations and case rates across the state," CDPH Director Dr. Tomás Aragón said Wednesday. "We are recommending masking in indoor public places to slow the spread while we continue efforts to get more Californians vaccinated."
The CDPH said that the new statewide measures were being instated because "90 percent" of the state's population reside in high-transmission areas defined by the CDC.
The U.S. has seen a near 47 percent increase in the number of coronavirus cases reported over the last seven days, according to data by the CDC.
The highly contagious Delta variant is responsible for roughly 83 percent of all reported U.S. COVID cases, according to the CDC.
As coronavirus cases are again on the rise in 90 percent of U.S. jurisdictions, a resurgence of mask mandates are being enforced from the federal government down in an attempt to slow the spread.
The latest announcement by the CDPH is not a mandate, though California became the first state this week to require all state and health care employees to provide proof of vaccination or be subject to weekly testing.
"We are now dealing with a pandemic of the unvaccinated, and it’s going to take renewed efforts to protect Californians from the dangerous Delta variant," California Gov. Gavin Newsom said Tuesday.
"As the state’s largest employer, we are leading by example and requiring all state and health care workers to show proof of vaccination or be tested regularly, and we are encouraging local governments and businesses to do the same."
California has doled more shots than any other state with over 44 million doses administered and roughly 75 percent of the state’s eligible population having received at least one dose of the vaccine.
Children under the age of 12 have yet to be approved to receive the coronavirus vaccine.