THAT SINKING FEELING : They bought homes next to a Duarte golf course that used to be a landfill. And then the ground slipped, the street buckled, walls cracked. Now 10 of them are suing the city and the developer.

When Gene Astuto moved into a new house across from the Rancho Duarte Golf Course in 1980, he could park his car on the street and walk right up to his front door. Now he has to walk slightly uphill, choosing his path carefully so he won’t step into any of the deep cracks in his lawn.

Several years ago, he abandoned plans to install a barbecue and spa in his backyard. The yard is so deeply rutted now that he almost never goes outside, and he has let his lawn go to weeds.

“I would never have bought if I had a hint something like this would happen,” said Astuto, who says that the land under the four-bedroom, 2 1/2-bath home for which he paid $115,000 is falling away from the foundation.

Like several of his neighbors, Astuto believes that his home was built too close to the former landfill on which the golf course was built. The homes are on Rancho Road just south of the golf course, and on Hacienda Drive just east of the golf course.

In a suit against the builder of the homes and the City of Duarte, 10 of the homeowners claim that the continued settling of the decomposed rubbish is damaging their property.

The homeowners contend that the unstable land has caused deep fissures to develop in their yards, creating hazards and lowering property values. Several homeowners have complained of structural damage, including cracks in exterior walls.

Homeowners also claim that methane gas has escaped from under the former landfill, despite the presense of a gas collection and disposal system installed by the city in 1980, and is leaking under the houses, endangering residents’ health.

The suit, filed in 1985, seeks more than $800,000 each for the homeowners to compensate them for damage to their homes and emotional stress.

“They (the homeowners) knew when they bought that they were adjacent to a dump, but what they didn’t know was that their properties were sitting on a trash fill,” said Joseph Liebman, attorney for the homeowners.

“The houses are sitting there and the ground is falling away from them,” Liebman said.

Although both the city and the builder, Kaufman and Broad, acknowledge some problems involving fissures and have taken steps to remedy them, neither accepts full responsibility.

“We feel this is an aesthetic problem that can be solved, and we have done that,” said John Cygul, director of corporate communications for Kaufman and Broad, which offered in 1984 to inject sand under pressure into the ground cracks. Only one homeowner accepted.

The city bought the closed landfill in 1978, covered it with soil and began work on a redevelopment project that included the nine-hole golf course and 122 homes.

But problems with the site came to light even before Kaufman and Broad began construction on the project.

The 32-acre, 40-foot-deep gravel pit was used as a disposal site for household trash from 1964 to 1971, when it was closed because it had reached capacity.

During site preparation, Kaufman and Broad discovered that the landfill was larger than Duarte had thought. The firm proceeded in its efforts to determine the boundaries and, in conjunction with the city, made what it thought were appropriate adjustments, said Edwin Mann of Kinkle, Rodiger and Spriggs, attorneys for the city. The major change involved adding extra soil to the site at city expense.

By the time it sold the homes, Cygul said, Kaufman and Broad thought the adjustments were behind them.

“We never thought there would be problems on the properties,” he said.

But problems began to appear soon after homeowners began moving into the development.

Astuto said the lawn had been installed when he bought his home. He put in some trees and bushes, and all went well for a time.

Astuto cannot pinpoint the date, but he said large cracks began to appear in his front yard, which then sank down and toward Rancho Road. He continued to tend his garden until the cracking unearthed and broke his sprinkler system.

“I thought, ‘To hell with it.’ ” Astuto said. “I lost interest in the whole house.”

Kaufman and Broad commissioned engineering studies, and a report prepared for the firm in 1983 showed that cracks had appeared on 13 home sites at or parallel to the landfill boundary.

The report stated that while no structural damage to homes had been found, continued settlement, if unchecked, could cause such damage.

“When (the cracking problems) were discovered, we jumped in there to try to solve them,” Cygul said.

But only one of the 13 homeowners with problems accepted the sand injection offer, which included a suggestion that homeowners follow up by topping off the cracks periodically with sand that the city would provide.

The others balked at a provision requiring them to sign a memorandum of understanding that they interpreted as waiving their rights to legal action against future problems involving the cracks.

Since then, Kaufman and Broad has settled with two other homeowners for undisclosed amounts, leaving 10 parties to the lawsuit.

Kaufman and Broad places some of the blame for the damage on the homeowners for refusing the offer. The firm contends that if they had accepted the offer in 1984, the damage would not been as extensive.

The homeowners “have refused to have anyone work with them to solve the problem, and they didn’t protect their houses in the interim,” said Thomas Winfield, an attorney for Kaufman and Broad.

“Kaufman and Broad never intended that they give up any rights for future claims for loss or damage, and homeowners were told that,” Winfield said.

Carol Ciminelli, who accepted Kaufman and Broad’s offer, is pleased with the results of the sand injection into a 3-inch-wide fissure that ran across her property.

And although the fissure has opened again since the sand injection 18 months ago, creating a one-inch gap, she said her situation “has improved 100%.” She plans to top off the crack as soon as time permits.

“If Kaufman and Broad had not responded, I would be angry too, but they have responded,” Ciminelli said.

Winfield said the land movement was most severe in the first two years after the homes were built, subsiding during the last five years. He said the ground will ultimately stabilize, but probably not before the late 1990s.

After he took the case, Liebman commissioned an engineering report for the homeowners. The results, released in June, confirmed Kaufman and Broad’s 1983 finding that there is decomposed rubbish under Rancho Road and next to the yards in which cracks have developed.

The report commissioned by Liebman, prepared by Lockwood-Singh & Associates, consulting foundations engineers and geologists, also noted cracks in the walls of the homes and said they were caused by settling of the decomposed rubbish in the former landfill.

Liebman plans to rely heavily on those findings when the case goes to trial, possibly next year.

The lawsuit is not the first instance in which the former landfill has posed problems for the city and the builder.

The city spent eight months in 1984 and 1985 reconstructing Rancho Road because it had tilted toward the golf course and sunk several feet, making it impossible to drive from the road onto the cul de sacs that issued from it.

At least half of the homes in the development have developed pin-sized holes in their copper pipes, causing water to leak through walls and foundations. The same problem exists in more than 1,000 homes built from 1978 to 1980 in several areas of the city.

The “pin-hole” problem, which has cost homeowners and builders thousands of dollars in repairs, is believed to stem from the interaction of the copper with the corrosive well water supplied to Duarte homes. In recent months, hundreds of residents have organized to try to force the city to find a solution.

Last month, the state ordered the city to pay $100,000 for tests to determine whether the groundwater under the landfill is contaminated.

But to those whose yards are filled with cracks, the land slippage is the more worrisome problem.

“I have never been in such a devastating position because I can’t get out of that house,” said Patricia Montreuil, who bought her home as an investment seven years ago from the original owner, who was transferred to another area.

“I would have sold two or three years ago if I could. But I can’t sell it because I would have to take a loss on it.”

Montreuil said she first noticed problems when her driveway started separating and gradually developed a six-inch crack. She thought it had been installed incorrectly and had it replaced.

“Then I saw the lawn splitting and the street dropping.”

The problems have been heartbreaking for Montreuil, whose initial love for her home has disintegrated into a love-hate relationship.

“It is a beautiful quiet area with the golf course and mountains as a view. I planted roses and took such pride in them. It was a labor of love,” she said.

“Now it is an albatross around my neck.”

Although he does not like his house, Astuto says he won’t try to sell until the lawsuit is resolved.

Astuto, who lives on a cul-de-sac off Rancho Road with an adult son, said his sidewalks are cracked and uneven in places and dangerous to walk on.

“I worry about kids and vendors coming onto the property,” he said.

Astuto said he is resentful that he cannot use his yard.

“The inside is OK, but the outside reminds me of the problems and kills the whole thing for me.”