The effective date for a new federal regulation requiring funeral homes to offer price lists was stated incorrectly Monday. The regulation becomes effective April 30.

Commercials for cremation, with a yacht taking ashes out to sea, now appear on television here. Gritty remains of recently dead Californians are being scattered from the Palm Springs desert to San Francisco Bay at costs so low that thousands more are joining what the funeral industry once derided as the "shake-and-bake crowd."

It is a revolution in the American way of death, brought on by the weaker family ties and burial traditions of the West, but now beginning to spread nationwide.

In 1982, a record 32.3 percent of all Californians who died were cremated. The rapidly growing demand for the relatively cheap ($500) "direct disposals," as the industry calls them, has created a boom in the crematory business. The once-resistant funeral industry has begun to see the advantages of going along with the trend, just as a new federal trade regulation is expected to give a major boost to a significant shift in national rituals.

In the last 10 years, the number of Americans having their remains cremated has jumped from 4.9 percent to 11.7 percent. Of the 1,984,700 deaths in 1982, 232,789 were followed by cremation, according to Jack Springer of the Cremation Association of North America. By the next century, he estimated, cremations will climb to 50 percent, moving toward the level of western nations like Britain, where 70 percent are cremated and a popular slogan calls for "Land for the Living."

Funeral industry experts expect cremation to become predominant much sooner in California, where 61,158 persons were cremated in 1982, many of them choosing to have their ashes scattered in San Francisco Bay, in the Sierra Nevada Mountains, in the ocean off Catalina Island and even under their favorite rosebushes. In Orange County, the cremation rate already is up to 40 percent and cemetery officials say they think it is even higher in some affluent parts of Marin, San Diego and Santa Barbara counties.

The practice is spreading despite a controversy over mass cremations that led last year to an $800 million lawsuit and a new state law to punish crematories that mix up ashes.

Proponents of cremation cite reasons besides cost. Mary Minaker of Livermore, Calif., said that when her father, Fred John Banley, a retired carnival concessionaire, died a month ago at 92, she followed his wishes and had him cremated. He will be interred in a plot one-third the size needed for a coffin. "He thought it was always better to preserve land for future generations," said Minaker, who plans to have her own ashes scattered in the Sierras.

Yesterday, the Federal Trade Commission's "Truth-in-Funerals" rule went into effect, requiring funeral homes to show price lists including the lower cost of cremation and forbidding funeral directors from demanding that families pay for embalming or for a casket for a soon-to-be cremated relative. Coffin and burial expenses add at least $1,000 to the cost of most funerals, said Marcia Goldberg, executive director of the Continental Association of Funeral and Memorial Societies.

Richard Jongordon, director of the Neptune Society of Northern California, said cremations are popular in California because "this is a transitory area, with people moving in and out, and there's been a breakup in the family bonds of the Midwest." With 70,000 members, Jongordon's group is one of the largest of the "memorial societies" that have sprung up throughout the West, and much of the rest of the country, to reduce funeral costs. Members pay a $20 registration fee, entitling them to a quick pickup of their remains once relatives call the society. The cremation and scattering, often done off San Francisco from Jongordon's yacht Naiad, cost about $500.

Jongordon, a former insurance agent and contractor in his fifties, took over the society in 1974. He remembered the four years he spent paying off the funeral debts for his first wife after she died of heart failure when both were in their twenties.

Along with Orange County attorney Betty McMullen, private investigator Walter Goode, and San Francisco attorney Melvin Belli, Jongordon has launched a campaign against practices that have generated the major lawsuit here and a recent $1.5 million judgment against a crematory in Florida, where the cremation rate is now 27.2 percent.

Edna Del Jiacco, a Huntington Beach resident who has joined the suit against a dozen Los Angeles and Orange County mortuaries, said she was "horrified, sick, guilty and then angry" when she heard reports that the crematory that handled the remains of her son, Rex, 28, engaged in mass cremations to save money.

Goode said he found evidence of "multiple cremations, commingling of ashes, extraction of gold fillings, mutilation of bodies" and other "reprehensible acts practiced by a disreputable segment of the industry."

The manager of the Harbor Lawn mortuary, one of the largest in Orange County and the focus of Goode's investigation, declined comment on the charges.

In response to complaints, the state legislature passed a law that took effect yesterday making commingling of ashes without the consent of next-of-kin a misdemeanor, but Goode, McMullen and Jongordon all called this inadequate.

In the introduction to its Truth-in-Funerals rule, the Federal Trade Commission noted that "a funeral is the third largest single expenditure many consumers will ever have to make, after a home and a car."

Consumer advocates support cremation as a way for low-income families to avoid wiping out their savings in funeral costs, but industry experts say poorer, blue-collar families still desire expensive funerals and burials. Those signing up with memorial societies and choosing cremation are more likely to be the well-educated and affluent, who are less bound by religion and tradition.

For decades, cremation has been far more popular in non-Roman Catholic foreign countries than in the United States. In Japan about 90 percent of the dead are cremated, a cultural tradition that helps explain why the cremation rate in Hawaii, with its large ethnic Japanese population, is 45.8 percent.

The Roman Catholic Church continues to recommend burial, said Paul Dotson, a Los Angeles priest who is vice president of the National Catholic Cemetery Conference. But old injunctions against cremation have been eased, he said, and the church now objects strongly only to the scattering of the ashes, preferring that they be interred.

Springer said the Cremation Association of North America is encouraging consumers to spend extra money to inter rather than scatter the ashes of their relatives, and thus have a place to visit and remember them by. A pamphlet has been prepared, entitled "Cremation Is Not the End."