Update 8.58pm: A 30-year-old father who had been missing after mudslides cascaded through Montecito earlier this week has been identified as one of the dead.
The Santa Barbara County Sheriff's Office says Pinit Sutthithepa's body was found on Saturday afternoon.
His two-year-old daughter, Lydia, is still missing.
Mr Sutthithepa's six-year-old son, Peerawat, and his father-in-law, 79-year-old Richard Loring Taylor, were also among the 20 people killed.
Authorities say four people, including Mr Sutthithepa's daughter, have been reported missing.
Friends have said Mr Sutthithepa arrived from Thailand, leaving behind his wife and two children but sending them money for years until he could bring them to the United States.
Parishioners prayed for those killed and for families still searching for missing relatives.
Because most churches in coastal Montecito remain in an evacuation area, many worshippers attended Sunday services in nearby towns.
At a church in Santa Barbara, they lit candles and prayed for families who lost loved ones.
They said the victims were their friends and neighbours.
In the disaster area, firefighters are going door to door to check the structural stability of homes damaged in the storm.
Recovery crews continue to work around the clock, digging away at the masses of mud, boulders and toppled trees.
Earlier: California mudslides death toll rises to 19
The death toll from the mudslides in California has risen to 19, authorities said.
The body of Morgan Corey, 25, was found in mud and debris in Montecito, Santa Barbara County Sheriff Bill Brown said. Her 12-year-old sister, Sawyer, had been found dead earlier.
Another person who had been on the list of missing, 62-year-old Delbert Weltzin, was found alive and well, Mr Brown said without elaborating on the circumstances.
The two developments reduced the number of missing from seven to five.
"While every hour it remains less likely that we will find anyone alive, there is always hope," the sheriff said.
The army of searchers and recovery workers in Montecito swelled to more than 2,000 five days after a powerful storm swept in from the Pacific and dumped a deluge on mountain slopes above the coastal enclave that were burned bare by a huge wildfire in December.
The backbreaking work went on in the summerlike weather that has made the stretch of Santa Barbara County coast about 90 miles northwest of Los Angeles a haven for the wealthy, celebrities and tourists.
"We have to do whatever it takes," said Capt Tom Henzgen, leader of a team from the Los Angeles Fire Department.
Long-range forecasts gave the crews about a week before the next chance of rain - and potential new mudslides - although the precipitation was expected to be disorganised and light. Another system was possible two days later.
Crews worked throughout the day on Saturday to clear debris basins and officials said there was still a lot more work to be done.
Tom Fayram, the deputy director of the county's flood control district, said the crews were making great progress and he was confident that at least a base level of water would be able to pass through the creek channels.
Much of the community of about 9,000 remained under mandatory evacuation orders, even unscathed areas, as crews both removed debris and worked to restore water, sanitation, power and gas.
All warnings and orders for neighbouring Summerland and Carpinteria were lifted.
Tanker trucks sucked muddy water from flooded sections of US 101, the only direct major artery between Los Angeles and the Santa Barbara region.
The California Department of Transportation abandoned an estimate of reopening the highway on Monday and said it was not known when the closure would be lifted.
Amtrak, which began restoring rail service two days after the flood, was adding cars to trains because of heavy demand. Two boat companies that normally take tourists out to Channel Islands National Park and on whale-watching excursions were ferrying people between the Ventura and Santa Barbara harbours.
Santa Barbara County said authorities were testing the ocean waters. Down the coast in Ventura County, environmental health officials warned that storm runoff can carry disease-causing bacteria and warned the public to avoid contact with ocean water until tests are reviewed next week.
In the disaster zone, searchers used chain saws and rakes to remove logs and sift through the remnants of what was left of multimillion-dollar homes. Crews with backhoes and jackhammers pulverised enormous boulders that were left when the torrents stopped.
Rescuers said they would search every piece of debris and pile of dirt to look for the missing.
The so-called Thomas fire, which led to the floods, was declared fully contained on Friday.
It erupted on December 4 in Ventura County and destroyed more than 1,000 structures as it swept through the city of Ventura and then threatened Carpinteria, Summerland and Santa Barbara.
At 440 square miles, it became the largest wildfire in California records.