Correction: An earlier version of this story misstated the amount of money Prince George’s County has offered to Joyce and Leonard Caveny to purchase their home. The amount has been corrected.

Joyce and Leonard Caveny don’t want to leave the home they have lived in for 35 years. (Michael S. Williamson/The Washington Post)

The landslide that ruptured a residential street in Fort Washington last year is the subject of a bitter legal rift, with residents accusing the Prince George’s County government of causing the collapse and leaving homeowners who may be forced to move elsewhere in financial ruin.

The county wants to condemn five properties and spend $15 million to shore up the hillside for the remaining 22 households. But three of the five homeowners refuse to go, saying the county is not offering fair compensation.

They are threatening to sue Prince George’s, saying that the May 5, 2014, landslide resulted from poor maintenance of roads and underground pipes, rather than from extended heavy rains and what the county deems “an act of God.”

The unhappy homeowners include Cherie and Daniel Myles Cullen, who in 2005 paid $560,000 for their house at the top of Piscataway Drive. The county has offered them $475,000 for the property, halfway between the assessed value of $425,000 and a private appraisal the couple got that valued the house at $525,000.

Map of the evacuated neighborhood along Piscataway Drive, in Prince George's County, Maryland.

“What they offered wasn’t even enough to cover my mortgage,” said Daniel Cullen, who with his wife has been paying rent on a townhouse in Alexandria for themselves and their two children.

The couple has exhausted their savings and stopped paying their mortgage. They are in negotiations with their bank, but an initial foreclosure notice arrived last month.

Then there are Leonard and Joyce Caveny, who have lived in their 3,600-square-foot home since 1980, filling it with countless artifacts of their eight-plus decades of life.

On one wall is a 1955 snapshot of Leonard Caveny as captain of the Georgia Tech gymnastics team, launching himself over the pommel horse. In another corner sits Joyce Caveny’s first sculpture — the clay head of an American Indian. Curio cabinets display scores of dolls dressed in ethnic threads.

The Cavenys submitted an appraisal to the county that understated their home’s square footage, a $200,000 mistake. They say the county refused to use a revised appraisal and offered them $431,000 on a home they believe is worth $628,000.

Even at a higher price, the Cavenys — Leonard is 80, and Joyce is 83 — dread leaving their longtime home. They have been living without water, phone or gas service most of the past year, using the bathroom of a neighbor, toting jugs and bottles of drinking water, cooking on a camp stove and collecting rainwater to tend to their garden.

“It’s almost impossible to replace what we have here,” Leonard Caveny said.

An engineering firm hired by the county after the landslide said it was caused by torrential rain that saturated a layer of Marlboro clay inside the hillside, triggering the slippage that upended trees, ruptured pipes and asphalt and sent dirt crashing onto the road below.

The landslide was a natural disaster and not the county’s fault, KCI Technologies said. A renovation plan that would include installing large steel beams into the hillside would make the neighborhood stable for most residents, the engineering firm said, save for those whose homes are atop the hill and would have to be condemned.

But residents challenged KCI’s findings from the outset. They said cracks had been appearing in the road for years, and water main breaks were a regular occurrence.

Using public records, photographic evidence, geological reports and a different engineering firm, they posited that the collapse of the hill was caused by water leaking from poorly maintained pipes underneath the asphalt.

What’s more, geotechnical engineer William Ryan maintained in his report that the road and neighborhood could be permanently repaired for a fraction of the cost of what the county was proposing.

The county has forged compensation agreements with two of the five hilltop homeowners, including the family of Andrew Bucci, an elderly artist who died seven months ago at age 92. Bucci had left his house on Piscataway Drive after the landslide and returned to his native Mississippi. His property and the other the county has claimed are now vacant, and work has begun to prepare them for demolition.

But the three holdout homeowners remain. Last week, after months of letters and a few meetings that left both sides frustrated, they sent an ultimatum to County Executive Rushern L. Baker III threatening to sue.

The county responded by filing an injunction that sought permission to evict them without paying any compensation at all.

“They expected the county to be reasonable,” attorney Joe Suntum said of the Cullens, the Cavenys and Tracy Rookard, an Army veteran who lived alone in her home on the hill. “Prince George's County is seeking to take our clients’ property . . . to avoid having to pay the owners just compensation.”

County officials say Baker felt obligated to do whatever he could to help the Piscataway residents — but also had to balance their situation against pressing needs that affect hundreds of thousands of county residents: struggling schools, a foreclosure crisis that has decimated household wealth, crime flare-ups in poorer neighborhoods, communities that lack basic retailing and other amenities.

Baker found $11 million in county funding and secured more than $4 million more in state and federal emergency funds to buy out the homeowners and stabilize the hillside — no small feat in a cash-strapped county that fought bitterly this spring over raising taxes to generate more money for schools.

Baker is “a family man,” said his top aide, Nicholas Majett. “He understands the importance of being at home and he charged his executive staff to keep all those families in their properties to the extent that we could.”

On Monday, a Prince George’s County Circuit Court judge ordered the county and the homeowners to undergo mediation to try to break their impasse.

Before the landslide, the Cavenys had planned to stay in their home as long as their health allowed it and had built out a guest bedroom in case they needed to hire a nurse to live with them.

Leonard Caveny, a renowned rocket scientist who was a part of a team studying antimissile defense systems under the Reagan and George H.W. Bush administrations, has kept detailed records and a timeline of events since the landslide, and he reviewed KCI’s work himself, hoping to find a way to change the county’s mind.

He and his wife say they have accepted that they will probably have to pack up their beloved collections at some point. Until then, they are enjoying their tranquil outdoor atrium, located in the center of the house, where two patio chairs sit amid the foliage of a man-made forest of exotic plants.

“I would rather stay here,” Joyce Caveny said this week, before pressing the button on a toy guitar that plays Johnny Cash’s “Ring of Fire.”