Amid the exposed pipes, sagging plaster and stopped-up toilets, two gleaming sinks and a fiberglass laundry tub appeared last week, the first tangible results of the Reagan administration's promise to transform the shelter for the homeless run by the Community for Creative Non-Violence in downtown Washington into a "model" for the nation.

Although that commitment, which could cost as much as $5 million, marked a turning point in care for the area's street people, it also underscored the difficulty of dealing with a complex and deep-seated social problem.

Obscured in the drama of the widely publicized hunger strike by CCNV leader Mitch Snyder and the midnight telephone negotiations with the White House that led to the unusual agreement last Sunday are some difficult and politically volatile questions.

Some advocacy groups and city officials question whether CCNV, loosely organized, $35,000 in debt and with little formal administrative experience, should continue to run the shelter at 425 Second St. NW. But the agreement announced by Health and Human Services Secretary Margaret Heckler appears to exclude the city pointedly, despite the Reagan administration's often-stated desire to return power to the states and the fact that it is the District of Columbia that must inspect the renovations.

Perhaps the most fundamental and difficult philosophical question is whether a massive shelter that concentrates 800 people in one location is the best way to improve the lives of the homeless.

These issues have assumed even greater urgency because of the passage last week of Initiative 17 on the D.C. ballot, the nation's first referendum requiring a local government to provide "adequate overnight shelter" for its residents. Nearly 75 percent of the District's voters approved the initiative sponsored by CCNV, despite a vigorous campaign against it by city officials and other advocates for the homeless.

Opponents argued that the initiative would result in the proliferation of shelters like CCNV's, which they say is little more than the contemporary equivalent of an 18th century poorhouse, a mammoth, dangerous place run by a small band of activists who impose few rules and, for the most part, are untrained in crisis intervention.

"They've created the very thing deinstitutionalization was supposed to avoid, which is a warehouse," said the Rev. Tom Nees, whose Community of Hope Church operates a shelter for a dozen families in Adams-Morgan.

"If the federal government is going to spend a big chunk of money like that, they should sit down and research it," said Nees, a member of the Mayor's Commission on Homelessness. "This is a reaction, not a creative response. We certainly have no way of controlling what the president and Mitch Snyder are going to do since they're not accountable to anyone. But nobody knows what effect this will have."

That includes Vernon Hawkins, the District's acting commissioner for social services, who said he learned of the agreement while watching television Sunday. He said federal officials told him 48 hours earlier they would not bow to Snyder's demand to appropriate millions of dollars to fix the shelter.

Hawkins said he still has not heard from federal officials but would like to meet with them to learn more about the arrangement.

Harvey Vieth, chairman of the federal task force on the homeless, who negotiated with CCNV, said last week that the agreement is especially unusual because of the administration's desire to return power to local jurisdictions.

"In every other city we've been working with, we've worked through the local government," said Vieth, who is overseeing repairs to the shelter. "I don't know what the city's role is at this time. It is not our role to work directly with the provider, but the main focus in all this was not Mitch Snyder, it was 800 homeless people. We simply could not find an alternative site [for a shelter], and that building was available."

Snyder, known for his confrontational style, said any relationship between CCNV and the city is predicated on certain conditions. "We're going to give it one last try," he said. "But unless the city is willing to deal with homelessness, my reaction is that I don't want them around, even if we have to beg for utility money."

Telephones at the shelter were disconnected last week for nonpayment, and Pepco has threatened to cut off electricity. Snyder, who is negotiating with several Hollywood producers to sell the film rights to his story, hopes to use proceeds to finance the shelter's operations, a monthly cost he estimates at $10,000.

Since the shelter opened in January, the District, which was given the surplus building by the federal government, has leased it to CCNV for $1. The city has provided routine police and emergency medical services. Because the shelter's sprinkler system does not work, the fire department has spent at least $200,000, according to a spokesman, for a nightly 12-hour fire watch by two firefighters stationed outside the building, which they privately refer to as "the Second Street Hilton."

Vieth said he assumes that CCNV will operate the refurbished shelter, but that no decision has been made. The sole responsibility of the federal government, he said, is to physically transform the shelter. The cost of maintenance and operating philosophy are the responsibility of the shelter's operator.

That is precisely what concerns some city officials and other advocacy groups who assume CCNV will continue to run the shelter.

Among those who have complained publicly about the shelter is Deputy Police Chief Issac Fulwood. He said officers have had to respond to increasing numbers of calls from neighbors -- especially the Hyatt Regency Hotel a block away -- as well as from shelter residents about crimes ranging from panhandling to rape. Police also complained that criminals use the shelter as a sanctuary, knowing CCNV will admit them -- but not police -- and not ask any questions.

"It's like being against mom, apple pie and the American flag," said Fulwood, "but spending $5 million to fix that building is not a comprehensive approach to the problems of homelessness in the nation's capital. That place is a disaster . . . . you can't have a facility with 600 to 800 people with varying problems" and expect otherwise.

Vieth said that neither he nor CCNV envisions that the model shelter will be a massive building with 800 people. "No one wants a situation like the New York Armory with 800 people in one room," Vieth said, referring to the Manhattan armory where as many as 1,400 men slept on cots in one room last winter.

According to CCNV, the tentative plan for its shelter is to subdivide the 40-year-old building into smaller shelters containing about 100 people each. As for complaints about crime, Snyder notes that police regularly take people they find on the street to the shelter.

Cliff Newman, one of two dozen CCNV staff members who live and work at the shelter, acknowledges that crime is a problem. He attributes it partly to the condition of the building -- there are no lockers and theft is common -- and to the people the shelter serves, many of them former mental patients, others desperately poor.

"We take the people no one else will," Newman said. "There have been a number of serious cutting incidents but they have been surprisingly few for a building of this size. And there haven't been any murders . . . . We've been trying to keep this place together with Band-Aids for months."

Central to the dispute is CCNV's operational style and its philosophy that "guests," CCNV's term for shelter residents, should run the place as much as possible and that any shelter, especially during the winter, is preferable to no shelter at all.

"People shouldn't have to do anything to get shelter," said CCNV member Carol Fennelly. "A shower doesn't get rid of lice anyway. We provide a less restrictive alternative because our desire is for people to get shelter, not drive them back to the streets. This is their home."

Sometimes this philosophy results in an atmosphere reminiscent of a psychiatric ward before the advent of major tranquilizers. Some people take their clothes off, talk to imaginary voices, defecate on the floor and wander glassy-eyed around the room. CCNV members say that many residents, especially the women, are former mental patients from St. Elizabeths Hospital.

"The difference between the [shelter] and Bedlam [the old infamous British mental hospital] is that Bedlam was locked and people couldn't get out, and the shelter represents a choice," said Dr. Eve Bargmann, an internist who has worked at the shelter's makeshift medical clinic.

"The shelter is chaotic and it's not a very organized place and it's manned by a couple of people who are utterly exhausted zombies, but at the same time it's an absolute godsend to people I've dealt with," Bargmann said.

"The notion that it's better to have people on the streets freezing is a very naive argument" generally advanced "by people who haven't seen anyone freeze to death," she said.

To Virginia Rulik, a softspoken great-grandmother who said she is "past 65," the best thing the federal government has promised to build is a laundry room. It has been very hard, she said, sharing the only sink with 90 women who are trying to wash their clothes and themselves.

Rulik spends her mornings sweeping the stained mustard-colored carpet in the trash-strewn day room, its cinder-block walls painted a garish pea green. She sometimes tries to bathe in the only working portable shower, which reeks of urine, then heads off with several shopping bags and her vinyl purse for Washington's museums, where she stays until the shelter opens again at 5:30 p.m.

Her bed is a cot with a scratchy Army blanket in a grimy hall. She sleeps there because she keeps her possessions, most of them clothing she found on the street, in a six-foot-tall heap of boxes.

An unfailingly polite woman with salt-and-pepper hair, Rulik is vague about her past or the circumstances that led her to the shelter last Easter. She says she lived abroad and for years owned a home in Bethesda. Now she spends her evenings writing letters or doing embroidery. She says her eight grown children are scattered across the country and her husband lives in Colorado.

"I'd really like to find another place to live," Rulik said over a recent dinner of chicken stew, doughnuts and canned fruit. "It's awful here, but I have no place else to go."