A U.S. District Court judge has backed Fairfax County's claim that it has the right to tax a piece of property now being leased by the U.S. government in Reston, a decision that will give the county about $4.6 million in taxes over the next 17 years.

In addition, Judge Albert V. Bryan determined that the county could keep $1.8 million it had already collected in taxes except for about $390,000 which it owes the federal government due to an error in calculating taxes on the property in 1976.

Board of Supervisors' chairman John F. Herrity hailed the decision, announced at the board meeting Moday, as a "victory for the taxpayers and for the county attorney's office." Judge Bryan made the decision July 7.

The litigation, initiated last January, involved the present headquarters of the U.S. Geological Survey on an 85-acre tract of land on Sunrise Valley Drive, Reston.

The property was acquired by the U.S. government 1966 and leased to Gulf Reston Properties, which agreed to construct a building on the site for the use of the U.S. government. The building was completed in 1973 at which time GRP re-leased the building for 20 years to the U.S. government for an annual rent of $5.5 million. At the end of the lease, title to the building will pass to the U.S. government.

This type of lease-purchase arrangement between the U.S. government and private developers is authorized by congressional legislation and there are about 90 similar agreements across the nation.

According to county attorney Robert Foley Flinn, the legislation state that the U.S. government will pay local property taxes until it takes over title to the property. Flinn said his office contacted over half of the other 90 ventures and discovered that the federal government was paying the property taxes without protest.

But according to William L. Shraberg, an attorney in the tax division of the U.S. Justice Department, the federal government claimed that the Reston project was entered into under legislation dating from 1949 which did not explicitly state that local property taxes had to be paid by the U.S. government.

In other matters, the board reiterated its support for the work of the county's Fair Campaign Practices Committee which is preparing new guidelines for candidates. Herrity abstained from supporting the endorsement because he said, "I think (the committee's) guidelines are too broad and impinge on the public's right to elect."

The board also approved Herrity's nomination of Gary L. Jones, as one of the two at-large members on the county's school boards. Jones is assistant to the president for administration at the American Enterprise-institute, a public policy research office.

Supervisor Martha V. Pennino (D-Centreville) expressed concern about the fact that the county was called upon to help douse the recent fire at the "tank farm" on Pickett Road. "We don't own the land on which the 'tank farm' exists, yet we become responsible for its safety," Pennino said.

Pennino recalled that there had been opposition to placing the tank farm where it now exists and she questioned whether Fairfax City, which allowed the rezoning to permit construction of the depository, has the capacity for fighting fires at the gasoline depasitory in the future.

Finally, the supervisors were informed that the county's historical commission has drawn up plans for ensuring that archaeological sites within the county will be inventoried and investigated before they are destroyed by development.