Like the weather, everybody talks about government waste, but no one seems to do anything about it.

Donald Lambro is trying to do something about it. He has written a book called "Fat City: How Washington Wastes Your Taxes" (Regnery/Gateway Inc. 405 pages. $12.95), in which he ferrets out federal agencies and programs that contribute to government waste and abuse. Lambro estimates that the amount of money the government wastes on unnecessary agencies and programs comes to about $100 billion a year -- or more than the entire federal budget in 1962.

"It seemed to me that during the debate that goes on endlessly year in year out over federal spending, there are a lot of generalities,but nothing of a very comprehensive nature has ever been done," Lambro said in an interview.

Lambro, who covers Washington for United Press International, spent three years combing the halls and offices of the federal bureaucracy, talking with staff members and looking at computer printouts.

In the first half of his book, he looks at 18 general areas that could be cut back or eliminated completely without any negative effects on taxpayers.

For example, the government spends between $1 billion and $1.5 billion every year selling itself. This giant public relations effort employs 20,000 public information officers, movie makers, broadcasters and advertising experts. Lambro writes that these public information programs "have been allowed to grow to such excesses that their curtailment should be one of the priorities of any effort to cleanse the government of its most wasteful manifestations. Federal programs that perform efficiently and effectively do not need to be sold to the American people."

Other programs that are high on Lambro's list include the "poverty business" which pays white-collar consulting companies a lot of money to study the poor, travel abuses by government employes that add up to $500 million a year and revenue sharing. The United States spends about $7 billion a year in revenue sharing. "The problem with revenue sharing is that we don't have the money to share," Lambro said.

The second half of the book, entitled "100 Nonessential Federal Programs," picks up where the author left off with his previous book, "The Federal Rathole," where he examined 50 wasteful federal agencies and projects. "I wanted to provide the taxpayers with a cross section of agencies, ones with very small expenditures and ones with very big expenditures," he stated.

Some of the bigger agencies Lambro would like to see less of include the Civil Aeronautics Board, the Federal Election Commission, the Interstate Commerce Commission and the Consumer Product Safety Commission.