For nearly two years, the mostly elderly Chinese immigrant tenants in a Chinatown residential hotel have been harassed and forced to live for months without working showers, sinks and toilets as the owners have worked to reposition the building as a dorm for young tech professionals and students, according to a lawsuit filed Thursday.

“These substandard conditions were brought about when the owners and operators turned the 68-unit SRO into a construction zone in an attempt to convert it from low-income housing” to space for more affluent residents, said Steve Collier, the attorney representing tenants of the single-room-occupancy hotel.

In the complaint, filed in San Francisco Superior Court, 55 tenants at 937 Clay St. say they have endured “broken showers, inadequate showers, showers kept locked and inaccessible to plaintiffs, lack of functioning toilets, toilets that are filthy and in a state of chronic disrepair.”

Paul Kuroda/Special to The Chronicle

The manager of the building, however, denies the building is being transformed for younger, wealthier tech workers.

“We are not kicking out any tenants,” said manager Tony Brettkelly of Latitude 38 Housing Services. “We are trying to improve the property.”

The lawsuit arrives at a time when San Francisco’s housing crunch has made the city’s stock of SRO hotels — long the housing of last resort for the poor — attractive to young professionals migrating to the city to take advantage of the tech boom. Several investment groups have snapped up SROs in the South of Market, North Beach and other neighborhoods.

The suit names the building’s current owner, 233-237 Eddy LLC, and manager, Latitude 38 Housing Services, and the former owner and manager, Clay Street Apartment Group and Urban Pioneer Management Inc. Dipak Patel, who owns several SROs in the city, controls the current owner.

While the average tenant pays $400 to $500 a month in rent, the current management firm is charging new tenants $1,095 a month for a room. That is up from $550 a month in 2013.

“There are ways to make money from vacant units and ways to renovate without taking out the vast majority of the services,” Collier said. “Nonprofits do it all the time.”

Residents say that for about a year there were only two showers and two toilets working in the building. Feng Xiao Chen, 81, said she would get up to shower at 2 a.m. because it was the only time there was not a long line. Some days she would hop on one of the free buses to Sonoma County casinos that leave from Chinatown and, after a two-hour drive, use the sinks there to wash up.

“It is always a race to use the showers and sinks,” said Chen, a retired seamstress and kitchen worker. “I try to let the younger people use them in the morning because they have to go to work.”

Guo Yi Deng, 61, said he and most of the men in the building have resorted to urinating in buckets because the toilets have been out of service so frequently.

Deng said he would have left the building, but he has “nowhere to go I can afford.”

Building manager Brettkelly said his company has moved quickly to fix problems since taking over the building in October. He said the company is investing $70,000 in wiring and $20,000 in fire safety.

Brettkelly said the four showers out of the original 10 still awaiting repair will be working soon and that the flooring in the hallways, bathrooms and kitchens will be replaced.

“If you saw it six months ago, you wouldn’t believe the condition of the kitchens,” he said. “The wiring systems were shot, and there were a bunch of notices of violations. It was a nightmare. There is still a ton of work to do, but we can’t do much until we have rewired the building. If you were to come back in six months, you would see a dramatic visual change.”

Throughout the building are signs threatening to fine tenants up to $300, and possibly evict them, for activities including walking on the fire escape, storing items in the hallway, using sinks to clean clothes, and leaving the bathrooms dirty. Collier said the signs, along with the endless construction, seem designed to make life unpleasant enough that tenants paying low rent will move.

While Latitude 38 manages buildings in SoMa and elsewhere that are very much marketed and designed for Millennial techies, this isn’t one of them, Brettkelly said. “We make it clear that this is a traditional Chinese immigrant building,” he said. “It’s not a student building or a tech building.”

Of the six units the company has leased since Latitude 38 took over in October, he said, four went to young people and two to family members of longtime residents. Counting tenants that were already in the building, about 12 of the rooms have been leased to younger professionals, he said.

But Gen Fujioka, policy director of the Chinatown Community Development Center, which organized the tenants, said the lawsuit is about “resisting efforts by a series of investors to exploit affordable housing in Chinatown.”

Latitude 38 is “taking over working-class housing, housing for seniors, housing for very low-income people, both here in Chinatown and other parts of the city,” he said. “This is a building that is clearly in transition. Half of it is clearly being designed not for this community, not for the existing tenants, and half of it is the older traditional housing.”

Supervisor Aaron Peskin, who represents Chinatown, called 937 Clay St. “an outrageous case” and said the neighborhood is the “final frontier” for investors looking to turn a profit in traditionally low-income neighborhoods.

“We have been getting increasing cases of SROs being turned into short-term rentals, of speculators trying to make a quick buck,” Peskin said. “As long as I am a supervisor, I am going to use every legal means at my disposal to make sure San Francisco’s Chinatown doesn’t go the way of New York and other Chinatowns that have been decimated.”

J.K. Dineen is a San Francisco Chronicle staff writer. Email: jdineen@sfchronicle.com

Twitter: @sfjkdineen