Mayor Marion Barry yesterday proposed a revised District of Columbia budget for next year that would further cut city services and require an average $34-a-year increase in household water and sewer bills.

Barry also disclosed to the City Council that as an economy move he is considering the elimination of or merger of several agencies that deal with special segments of the population, including Hispanics, women, the elderly and minority businesses. He said the city also sharply cut its public relations activities.

In addition to carrying out a cutback of the police force by 204 officers, as indicated earlier, the revised budget would cut the number of welfare eligibility investiagtors from 43 to 14, close four indoor swimming pools during the summer months, eliminate one of the city's 51 firefighting companies and abandon plans for opening the downtown central library on Sundays.

The curtailments are included in Barry's recommendations for changes in the city's $1.5 billion operating budget for the 1981 fiscal year, beginning Oct. 1. That budget now is pending before Congress.

Barry's amended budget proposals were a response to a set of recommendations made last week by his budget director, Gladys W. Mack.

Mack proposed that 3,000 authorized city jobs be eliminated in the coming fiscal year, in addition to 500 that would be dropped under the original version of the 1981 budget -- a total of 3,500. Of these, 1,000 would have required layoffs. However, Barry's recommendation yesterday called for cutting a total of 3,400 positions, including a total of 600 by layoffs.

Mack said some of the layoffs would be offset by hiring about 200 new workers to fill critical new positions.

Originally, the District of Columbia had expected to have 32,747 employes on the city-financed payroll at the end of the next fiscal year. The version cuts that to 30,278, a drop of 7 1/2 percent.

Barry's proposals require action by the City Council before the revised budget goes to the White House and then to Congress.

Individual items in the budget "are not sacred," Barry said, "but what is sacred is the dollar level . . . We've got to stay within that dollar level or we're going to get in trouble . . ."

Although the revised budget with its program reductions is billed as a cost-cutting measure, it actually is $29.7 million larger than the original version -- an increase required, Barry said, by a change in the city's budget accounting system needed to avert future deficits.

Barry's proposals would do little to ease the serious financial problems that are engulfing the city this fiscal year. The city is faced with a budget gap of at least $170 million between revenues and expenditures.

Beyond saying that the city may borrow from the U.S. Treasury to help make up this gap, Barry refused yesterday to forecast the actual cash deficit. Other efforts to close the gap by increasing revenues have run into trouble in Congress and on the City Council.

Barry said financing the higher cost of more intense sewage treatment at the city's newly expanded Blue Plains facility would require the first increase in water and sewer rates since 1976.

The combined rates would be increased 35 percent, raising the average consumer's bill $33.66 per year to $168.28. Barry said most suburbanites already pay higher rates.

Layoffs would be concentrated in the Department of Human Services, which would lose 271 current employes, and the police department, which lose 204 officers by layoffs in addition to 250 other uniformed and civilian positions by attrition.

Despite warnings by Police Chief Burtell M. Jefferson that reductions would pose a danger of rising crime, Barry said the cuts largely would be in desk jobs. "The front-line patrol force out in communities will be maintained," he said.

The four indoor swimming pools that would be closed during the summer starting next year would be at Woodson High, Sharpe Health, Washington Highlands and Shaw schools. Operating hours would be reduced at outdoor pools, with facilities opening in June, a month later than normal.

Barry also proposed funding for the city school system that could mean a loss of 786 of the currently authorized 9,655 jobs, depending upon a final decision by the school board.

Barry's letter to the council disclosed the possibility of various reorganizations that could merge the Office of Aging into the Department of Human Services, the Office of Latino Affairs and the Commission for Women into the Office of Human Rights and the Minority Business Opportunity Commission into the Department of General Services.

Any budget gap remaining when the current fiscal year ends on Sept. 30 will in effect, be added to a hidden "carryover" city budget deficit currently estimated at $284 million by Arthur Anderson and Co., an auditing firm hired by the city.

This hidden deficit, Barry told the council, is the legacy of federal accounting procedures followed since the days before the advent of home rule of 1975, according to reports submitted by Andersen and Lazard Freres and Co., a New York investment banking house now serving as the city's principle financial adviser.

Under the federal system, which Barry says he intends to abandon for the first time in 1981, the city government was able to spend more money than it actually received by delaying payment of some of its bills until the next fiscal year -- much as a worker delays paying this week's bills until he gets next week's paycheck.

"The federal system is the path to bankruptcy," Barry said, though he added that even with the $284 million carryover deficit the city is now now close to being bankrupt.

Barry said that within 60 days he hopes to develop a plan for gradually eliminating the hidden deficit. The 1981 budget, he said, will be truly balanced and will not add to the deficit.

The auditors also reported that the District of Columbia has failed to fund $739 million in pension liabilities. However, they said the pension deficit was "not an emergency," since it will be years before the money actually has to be paid out to retiring city workers.