LOS ANGELES — The “House of Contentment” has vanished, and its elderly owners are missing — just two of the 17 people who still can’t be found after muddy rainwater and debris killed at least 17 others in Southern California.

Bill and Alice Mitchell moved into their dream retirement home in the ritzy Montecito area of Santa Barbara County in 1999. They’d painted the phrase “Case de Contenta” on the side — “House of Contentment,” in Alice Mitchell’s words, according to Megan Alice Mitchell, the couple’s granddaughter

Until it was washed away this week by raging floods, leaving only a moonscape of mud and rocks, the three-bedroom Spanish-style house at 319 Hot Springs Rd. had been a sunny place filled with the artworks collected by Alice Mitchell, who steadied art in college, Megan Mitchell told NBC News on Wednesday.

“My dad [the Mitchells’ son] texted to say he’d been trying to contact them,” Megan Mitchell said. But when a relative went to the sheriff’s office for information, “they told her there was no 319 Hot Springs Rd. anymore.”

Only last month, the Mitchells had evacuated the house because of the threat of wildfires racing through the region. They’d moved back home only about a week ago, their granddaughter said.

She’s still holding out hope that her grandparents are alive somewhere. But they’re in their late 80s, and they have difficulty moving.

“My grandfather was really funny,” Mitchell said. Then she stopped herself. “Is funny,” she corrected.