The owners of a Beltsville sewer and water construction company were accused of violating state income tax laws in charges filed yesterday by the Maryland attorney general in local circuit courts.

Marvin F. Bosley, president of Suburban Utilities Contractors Inc., was accused in papers filed in Prince George's County Circuit Court of submitting a false personal state income tax return. Otha D. Upchurch, the company's secretary, was charged with submitting a false personal return in similar papers filed in Anne Arundel County Circuit Court.

Bosley and Upchurch are the second pair of sewer and water contractors to be charged in the last month as a result of a continuing state investigation. The investigation began in August 1980 after a series of articles on the Washington Suburban Sanitary Commission in The Washington Post.

The Post's stories detailed allegations of bid-rigging and price-fixing on contracts awarded by the WSSC, the public agency that builds and maintains water and sewer lines in Prince George's and Montgomery counties. The stories, which led to the revamping of contract-letting procedures by the WSSC, reported that a group of five local contractors, including Suburban Utilities Contractors Inc., had cooperated in bidding on WSSC contracts for connecting new homes to existing water and sewer lines.

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

The most recent charges also are a product of a joint investigation by the criminal investigations and antitrust divisions of the attorney general's office. Both Bosley and Upchurch are accused of underreporting their incomes on 1980 tax forms.

Bosley, a Laurel resident, listed his 1980 income as $139,436, and Upchurch, who lives in Millersville, listed his income at $139,649, investigators records show. Bosley and Upchurch face maximum penalities of 18 months in prison and $5,000 fines if convicted of the charges.

Gerald Martin, lawyer for the two men, said he expected to resolve the case before it came to trial.