Robert Latta, the Denver water meter reader charged with unlawful entry after he was found wandering around in the White House on the day President Reagan took the oath of office, ended up in the D.C. Jail yesterday after his bond was increased by a Superior Court judge perturbed over some of Latta's more recent wanderings.

On May 1, when Latta failed to appear before Judge Paul F. McArdle for a hearing, prosecutors reported that he had been seen earlier at the U.S. Capitol, where he said he wanted to make a speech on the Senate floor.

Later that week, Latta was arrested in Denver on a bench warrant, issued by McArdle, and ordered to return to D.C. court yesterday. He did.

When court convened, prosecutors charged him with failure to appear at the last hearing and asked that his bond be increased. The judge agreed, despite protestations by Assistant Public Defender Peter Krauthamer that Latta "appreciates his duty to appear."

Replied McArdle: "Well, I'm not appreciative of the fact that he can go to the Senate . . . and fail to appear here. I'm going to impose $5,000."

Krauthamer said Latta, who supports his elderly mother, would probably not be able to raise the money.

Meanwhile, Latta, whose case has received nationwide attention, is getting some help from high places.

Rep. Patricia Schroeder (D-Colo.) sent a letter May 9 to U.S. Attorney General Edwin Meese III saying, according to her press aide, "Don't you think there might be some way of sensibly resolving the Latta case. The prosecution of this case is reaching extraordinary proportions." So far, she has received no response, a spokesman said.

The spokesman also said she called the U.S. attorney's office here to see if the case "could be handled more expeditiously."

To that, U.S. Attorney Joseph E. diGenova said: "We handle all matters in this office with all deliberate speed, and this one will be handled similarly -- by the book."