The president and vice president of a Beltsville water and sewer construction company were charged with tax violations yesterday in papers filed by the Maryland attorney general in Prince George's County Circuit Court.

Frank T. Hauser Jr. and Lee Ganey Jr., the owners and officers of Tri-County Utilities Inc., were accused of seven counts of personal and corporate income tax violations, and Hauser, the company's president, was charged with obstruction of justice for withholding company bank records subpoenaed by investigators.

State prosecutors said the charges are the first to stem from a continuing investigation that was prompted by a series of three articles in August 1980 in The Washington Post. The stories detailed allegations of bid-rigging and price-fixing on contracts awarded by the Washington Suburban Sanitary Commission, and led to the revamping of contract-letting procedures by the public agency, which builds and maintains water and sewer lines in Prince George's and Montgomery counties.

The Post reported that a group of five local contractors, including Tri-County Utilities, Inc., had cooperated in bidding on WSSC contracts for connecting new homes to existing water and sewer lines.

For the past 19 months, investigators from the criminal investigations and antitrust divisions of the attorney general's office have been investigating allegations that sewer and water contractors profited from prearranged prices and agreements not to compete for bids on WSSC jobs, thus raising sewer and water costs to consumers in the two suburban counties.

The WSSC reorganized its construction contracting practices in December 1980 in an effort to make the bidding practices more competitive. Since then, prices on some jobs dropped as much as 27 percent.

"The investigation began with bidding and price-rigging and in the process we discovered the tax evasions," said Charles O. Monk II, chief of the antitrust division.

Last year, Tri-County had $906,000 worth of contracts with the WSSC, and in 1980, the company was committed to $1.6 million in sewer and water pipeline work, according to WSSC spokesman Marjorie Johnson. WSSC General Manager Robert McGarry said, through a spokesman, that "it would be inappropriate to make a statement. Any matter of this type is out of our hands."

Hauser and Ganey were unavailable to comment.

The "criminal informations" announced yesterday are similar to indictments handed down by grand juries. A grand jury had been investigating the alleged bidding and pricing irregularities until its term expired last November.

State prosecutors said they have been going over tax returns of about a dozen company officials, but that they have been "stonewalled" by them. They said they hope the tax charges against Hauser and Ganey will give them "leverage" to continue the investigation.

Hauser and Ganey face five counts of tax perjury, which carry a penalty of up to 10 years imprisonment each, and two lesser counts. The obstruction of justice charge against Hauser arises from his failure last July, while under subpoena, to disclose a company bank account at Citizens Bank and Trust of Maryland. He is scheduled to be arraigned April 16 in Prince George's Circuit Court. Ganey's arraignment is set for April 26.

According to the two five-page documents filed by Maryland Attorney General Stephen H. Sachs yesterday, Hauser and Ganey falsely reported their personal incomes on 1979 and 1980 Maryland state tax returns and in 1979, 1980, and 1981 filed state corporate returns that were "willfully and corruptly false."

Hauser listed his 1979 income at $81,896, and his 1980 income at $68,030 and Ganey reported his 1979 income as $80,511, and his 1980 income at $78,651, which reportedly were about 75 percent of their incomes.

Some of the unreported income allegedly resulted from the company's WSSC contracts. Tri-County Utilities reported corporate incomes of $91,201 in 1979; $30,092 in 1980, and $134,615 in 1981.

Sachs said charges against other individuals are anticipated.