In the shower room, six new stalls with hot and cold water stood upright against a painted wall. Overhead, newly installed water pipes connected with eight more showers on the second floor. In the hallway, lighted exit signs marked the doors. A sprinkling system to prevent fires now supplemented hand extinguishers.

Plumbers and electricians have been working for the past months at the nation's only federally owned shelter for the homeless poor. One subfreezing night last week, 780 men and 108 women were welcomed at the two-story, block-long structure a half-mile west of the Capitol. Up to $300,000 in renovation money has been provided by the District of Columbia government. The federal government owns the building. Staffing is by the Community for Creative Non-Violence, a 15-year-old group that, after the Catholic Worker house of hospitality in the Bowery of New York, is America's largest direct deliverer of services to the outcaste poor.

No other shelter has received as much attention, negative or positive. In 1984, President Reagan promised to turn it into a "model" facility, and then retreated to watch administration officials spend a year trying to evict the poor people who lived there. This was the first time anyone could remember that a politician sought to make the homeless shelterless. Some succor came two months ago when a Hollywood film company recruited extras among the homeless for a CBS-TV movie on the career of Mitch Snyder, the shelter's director.

As an issue of public policy, homelessness is entering its second phase. The first occurred about 10 years ago when Snyder and others began pointing to street people huddled around garbage fires and saying that they were human beings, not faceless winos, bums or psychos. Skid row was Pennsylvania Avenue in Washington and Broadway in New York. Mayors appointed commissions and task forces. Congress held hearings. Money was provided, including $70 million in 1984 in federal emergency funds. Churches and service organizations opened shelters and soup kitchens. A peak, of sorts, occurred in the State of the Union speech last month when the president singled out Trevor Ferrell, the Philadelphia teen-ager who has been serving the homeless for three years.

In phase two, the heroic people who operate shelters, gather food and organize volunteers are saying that for large numbers of people homelessness isn't an accident of rotten luck: It's the result of deliberate policy decisions by public officials. In 1981 the President's Commission on Housing said that America had more than 7 million low-income rental households. These families lived in either substandard housing or were paying as much as a third of their income for rent. Five years after that report, according to Barry Zigas, president of the National Low Income Housing Coalition, "federal housing assistance has been cut by 60 percent, and the nation has been at a virtual standstill [on] adding new subsidized units to the stock."

The effects are visible at any shelter. On the cots and the soup lines are citizens who came in during an emergency after losing their job, then their apartment or home. They have no chance to return to low-income housing because there isn't any available. What Rep. Henry Gonzalez discovered last year is typical. The chairman of the House subcommittee on housing and community development visited a northern Virginia co-op of 51 low-income units. He was told that for the rare vacancies an average of 44 applications were submitted daily. Last year, New York City had 177,000 public housing units, with 180,000 families on the waiting list. The coalition reports that 8 million low-income households can afford housing but that only 4.2 million units are available.

The Department of Housing and Urban Development tells the displaced and unplaced, don't come to us. The list is long of low-income housing programs proposed for elimination in the 1987 budget: rental rehabilitation grants, rental-housing development grants, Section 202 housing for the elderly or handicapped, public-housing development, farm-labor housing, low-income housing repair grants and low-interest loans to the poor.

Poverty has its lead time. People hurt by cuts in 1982 and 1983 are now shuffling into the shelters as the defeated and despairing. The programs being killed today, in turn, are producing tomorrow's shelter population. The war on housing programs, like every war, is producing refugees. In past weeks, the media have been telling their stories, of citizens in shelters who have not lost their minds, nor their health nor their dignity, but only a place to live. In time, the other losses to body and soul are likely to come. Groups like the Community for Creative Non-Violence offer a type of kindness that can't be bought, but a deadly erosion of the spirit hits nearly every person who stays at a shelter.

The special insult this winter occurred in the State of the Union speech. When Reagan patted the young back of Trevor Ferrell, he was giving the youngster the most cynical of messages: You keep doing your job for the poor and I'll keep doing my job on the poor.